U.S. patent application number 09/935712 was filed with the patent office on 2002-05-09 for toner for developing electrostatic latent image, process for producing the same, and process for forming image.
This patent application is currently assigned to FUJI XEROX CO., LTD.. Invention is credited to Daimon, Katsumi, Fukushima, Norihito, Hamano, Hirokazu, Imai, Takashi, Serizawa, Manabu.
Application Number | 20020055050 09/935712 |
Document ID | / |
Family ID | 26598744 |
Filed Date | 2002-05-09 |
United States Patent
Application |
20020055050 |
Kind Code |
A1 |
Serizawa, Manabu ; et
al. |
May 9, 2002 |
Toner for developing electrostatic latent image, process for
producing the same, and process for forming image
Abstract
A toner for developing an electrostatic latent image, a process
for producing the same and a process for forming an image using the
same are provided. The toner is produced by a simple production
process, with good reproducibility, particularly in particle size
and particle size distribution. The toner is excellent in
production stability, with a wide fixing region, and is also
excellent in low temperature fixing property, production stability,
storage stability of resin particles formed by the aggregation
process, and charging property, particularly environmental
stability and time-lapse stability. The toner for developing an
electrostatic latent image contains a crystalline resin having a
melting point as a binder resin, and at least one of an ester
compound having an alkyl group having from 6 to 32 carbon atoms and
a resin having a contact angle with water that is smaller than that
of the crystalline resin.
Inventors: |
Serizawa, Manabu;
(Minamiashigara-shi, JP) ; Daimon, Katsumi;
(Minamiashigara-shi, JP) ; Fukushima, Norihito;
(Minamiashigara-shi, JP) ; Imai, Takashi;
(Minamiashigara-shi, JP) ; Hamano, Hirokazu;
(Minamiashigara-shi, JP) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
P.O. BOX 19928
ALEXANDRIA
VA
22320
US
|
Assignee: |
FUJI XEROX CO., LTD.
Minato-ku
JP
|
Family ID: |
26598744 |
Appl. No.: |
09/935712 |
Filed: |
August 24, 2001 |
Current U.S.
Class: |
430/108.4 ;
430/108.1; 430/111.4 |
Current CPC
Class: |
G03G 9/09791 20130101;
G03G 9/08791 20130101; G03G 9/08795 20130101; G03G 9/09733
20130101; G03G 9/08797 20130101; G03G 9/08782 20130101 |
Class at
Publication: |
430/108.4 ;
430/108.1; 430/111.4 |
International
Class: |
G03G 009/097 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 30, 2000 |
JP |
2000-260311 |
Oct 3, 2000 |
JP |
2000-303912 |
Claims
What is claimed is:
1. A toner for developing an electrostatic latent image comprising:
a crystalline resin having a melting point as a binder resin; and
at least one compound which is selected from A) an ester compound
having an alkyl group having from 6 to 32 carbon atoms and B) a
resin having a contact angle with water that is smaller than that
of the crystalline resin.
2. The toner for developing an electrostatic latent image as
claimed in claim 1, wherein the toner satisfies the following
property: when the temperature is changed within a temperature
range of about from 40 to 110.degree. C., values of a storage
elastic modulus and a loss elastic modulus have an area which is
changed by 10.sup.2 or more per a temperature difference of
10.degree. C.
3. The toner for developing an electrostatic latent image as
claimed in claim 1, wherein the toner has a storage elastic modulus
at 30.degree. C. at an angular frequency of 1 rad/sec of about
1.times.10.sup.5 Pa or more.
4. The toner for developing an electrostatic latent image as
claimed in claim 1, wherein the toner further comprises a releasing
agent.
5. The toner for developing an electrostatic latent image as
claimed in claim 1, wherein the ester compound has a molecular
weight of about from 200 to 1,500.
6. The toner for developing an electrostatic latent image as
claimed in claim 1, wherein the crystalline resin is a polymerized
monomer which contains a sulfonyl group-containing monomer.
7. The toner for developing an electrostatic latent image as
claimed in claim 1, wherein the toner satisfies the following
equation (1):0.ltoreq..vertline.log GL(Tm+20)-log
GL(Tm+50).vertline..ltoreq.1.5 (1)wherein Tm represents a melting
point of the toner, GL(Tm+20) represents a storage elastic modulus
at Tm+20.degree. C., and GL(Tm+50) represents a storage elastic
modulus at Tm+50.degree. C., and the following equation
(2):0.ltoreq..vertline.log GN(Tm+20)-log
GN(Tm+50).vertline..ltoreq.1.5 (2)wherein GN(Tm+20) represents a
loss elastic modulus at Tm+20.degree. C., and GN(Tm+50) represents
a loss elastic modulus at Tm+50.degree. C.
8. The toner for developing an electrostatic latent image as
claimed in claim 1, wherein the toner has a loss tangent tan
.delta. at Tm+20.degree. C., where Tm represents a melting point of
the toner, satisfying 0.01.ltoreq.tan .delta..ltoreq.2 at an
angular frequency of 1 rad/sec.
9. The toner for developing an electrostatic latent image as
claimed in claim 1, wherein the resin has a contact angle with
water that is smaller than that of the crystalline resin, the
contact angle with water being about from 30 to 120.degree..
10. The toner for developing an electrostatic latent image as
claimed in claim 1, wherein the resin has a contact angle with
water that is smaller than that of the crystalline resin by about
3.degree. or more.
11. A process for producing a toner for developing an electrostatic
latent image comprising the steps of: mixing by agitating a binder
resin particle dispersion and an aggregated particle stabilizer
dispersion to prepare an aggregated particle dispersion containing
the binder resin particles; and heating the aggregated particle
dispersion to a temperature higher than a melting point of a
crystalline resin to form toner particles.
12. The process for producing a toner for developing an
electrostatic latent image as claimed in claim 11, comprising the
steps of: mixing by agitating a binder resin particle dispersion, a
colorant particle dispersion and an aggregated particle stabilizer
dispersion to prepare an aggregated particle dispersion containing
the binder resin particles and the colorant particles; and heating
the aggregated particle dispersion to a temperature higher than a
melting point of a crystalline resin contained in the binder resin
to form toner particles.
13. The process for producing a toner for developing an
electrostatic latent image as claimed in claim 11, wherein the
aggregated particle stabilizer is an ester compound having an alkyl
group having from 6 to 32 carbon atoms or a resin having a contact
angle with water that is smaller than that of the crystalline
resin.
14. A process for forming an image, comprising the steps of:
forming an electrostatic latent image; developing the electrostatic
latent image with a developer to form a toner image; transferring
the toner image to a fixing substrate; and fixing the toner image
to the fixing substrate, wherein the toner for developing an
electrostatic latent image as claimed in claim 1 is used to form
the toner image.
15. The process for forming an image as claimed in claim 14,
wherein in the fixing step, a contact time of a fixing member and
an unfixed image on the fixing substrate is adjusted to a range of
about from 0.01 to 0.05 second.
16. The process for forming an image as claimed in claim 14,
wherein in the fixing step, a belt type fixing unit is used.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a toner for developing an
electrostatic latent image that is suitable for forming a high
quality image by an electrophotographic process, a process for
producing the same, and a process for forming an image.
[0003] 2. Description of the Related Art
[0004] A process for visualizing image information through an
electrostatic latent image is being widely applied to various
fields. In the electrophotographic process, an electrostatic latent
image is formed on a photoreceptor through a charging step and an
exposing step, and the electrostatic latent image is visualized
through a developing step, a transferring step and a fixing
step.
[0005] In the electrophotographic process, an electrostatic latent
image formed on a photoreceptor through a charging step and an
exposing step is developed with a developer and then transferred.
The toner on a fixing material through the transferring step is
heated and melted by a fixing member having a heating unit in the
fixing step, whereby the toner image is fixed on the surface of the
fixing material. In the fixing step, the fixing member heats not
only the toner but also the fixing material to the necessary
temperature, so as to fix the toner on the fixing material. When
the heating of the fixing material is insufficient, so-called cold
offset occurs, in which only the toner is melted, and the toner is
adhered on the fixing member. When the heating is excessive,
so-called hot offset occurs, in which the viscosity of the toner is
decreased, and a part or the whole of the fixed image is adhered on
the fixing member. Therefore, the heating by the fixing member
necessarily falls within a fixing region, in which the cold offset
and the hot offset do not occur.
[0006] According to an increasing demand for energy saving, the
fixing temperature of the toner is necessarily decreased in order
to realize energy saving of the fixing step, which consumes a
certain extent of the consumed electric power of a duplicator, and
enhancement of the fixing region. The decrease in the fixing
temperature of the toner not only realizes the energy saving and
the enhancement of the fixing region, but also shortens the
so-called warm-up time, i.e., the latency time until the surface of
a fixing roll reaches the temperature capable of conducting fixing
upon turning on a duplicator, and enhances the service life of the
fixing roll.
[0007] When the fixing temperature of the toner is lowered, it
brings about decrease of the glass transition point of the toner to
cause such a problem that the storage stability of the toner is
deteriorated, and thus both the properties cannot be attained at
the same time. In order to realize both the low fixing temperature
and the storage stability of the toner, it is necessary that the
toner has the so-called sharp melt property, i.e., the viscosity of
the toner is quickly lowered at a high temperature region while the
glass transition point of the toner is maintained at a high
temperature.
[0008] However, because a resin used in the toner generally has
fluctuation ranges in the glass transition point and the molecular
weight, it is necessary that the composition and the molecular
weight of the resin are uniformed to obtain the sharp melt
property. In order to obtain such a resin, the molecular weight of
the resin is necessarily uniformed by employing a special
production process or by treating the resin with chromatography,
whereby the production cost of the resin is considerably increased.
Furthermore, it is not preferred from the standpoint of
environmental protection since an unnecessary portion of the resin
is formed.
[0009] As a method for lowering the fixing temperature of the
toner, the use of a crystalline resin as the binder resin is
proposed (as described in Japanese Patent Laid-Open Nos.
129867/1987, 170971/1987, 170972/1987, 205365/1987, 276565/1987,
276566/1987, 38949/1988, 38950/1988, 38951/1988, 38952/1988,
38953/1988, 38954/1988, 38955/1988, 38956/1988, 1217/1993,
148936/1994, 194874/1994, 5056/1993 and 112715/1993).
[0010] Although the fixing temperature can be lowered by these
methods, since the gradient of the viscosity of the resin with
respect to the temperature change is large, the sufficient
viscosity cannot be obtained upon production of the toner, for
example, upon kneading, and thus the dispersibility of a colorant
and a releasing agent in the resin is not stabilized, whereby such
a problem occurs that a toner having unevenness in the coloring
property and the fixing property is liable to occur. Furthermore,
pulverization of the kneaded product becomes difficult to cause
such a problem that a toner having a small particle diameter is
difficult to be obtained.
[0011] In order solve the problems, a method can be employed in
that an auxiliary agent, such as a thickening agent and a
pulverizing aid, is added, but is not preferred since these
auxiliary agents are dispersed in the resin to deteriorate the
crystallinity of the binder resin.
[0012] In recent years, an aggregation and coalescence process is
proposed as a process for producing a toner, the particle shape or
the surface composition of which is controlled according to the
purpose (Japanese Patent Laid-Open Nos. 282752/1988 and
250439/1994). The aggregation and coalescence process is conducted
in the following manner. A resin particle dispersion is produced by
an emulsion polymerization process or a dispersion emulsification
process, and separately, a colorant dispersion having a colorant
dispersed in a solvent is produced. The dispersions are mixed to
form aggregated particles having a diameter corresponding to a
toner particle diameter and then subjected to heating and fusing to
obtain toner particles. According to the aggregation and
coalescence process, the toner shape can be arbitrarily controlled
from an irregular shape to a spherical shape by selecting the
conditions for heating temperatures.
[0013] It is general in the aggregation process that the resin
particles are heated to a temperature near the glass transition
temperature to partially melt the surface of the resin particles,
whereby the aggregated particles are easily produced, and the
crystalline resin can be subjected to the formation of aggregated
particles. However, because the surface of the crystalline resin
particles suffers great change in viscosity particularly near the
melting point, the temperature range, within which the surface of
the resin particles can be partially melted, is narrow in
comparison to an ordinary noncrystalline resin. Thus, in the case
where the aggregation temperature is low, the aggregated particles
are unstable and easily broken, and in the case where the
aggregation temperature is high, the particles are easily grown to
cause a problem in that the controllability in particle size is
deteriorated. In the case of the aggregation process using the
crystalline resin, it is necessary to obtain emulsified particles
that some kind of a dispersant or a hydrophilic functional group is
contained in the resin, and it is not preferred since the
crystallinity of the resin is deteriorated.
SUMMARY OF THE INVENTION
[0014] The invention has been made in view of the foregoing
circumstances to solve the problems associated with the
conventional toner, particularly a full color toner, for developing
an electrostatic latent image, and is to provide:
[0015] (1) A toner for developing an electrostatic latent image and
a developer for developing an electrostatic latent image that has a
wide fixing temperature range and are excellent in fixing property
at a low temperature;
[0016] (2) A toner for developing an electrostatic latent image and
a developer for developing an electrostatic latent image that are
excellent in charging property, particularly in environmental
stability and time-lapse stability;
[0017] (3) A toner for developing an electrostatic latent image and
a developer for developing an electrostatic latent image that can
be easily produced, and are excellent in reproducibility of the
particle shape and the particle size distribution and excellent in
production stability;
[0018] (4) A toner for developing an electrostatic latent image and
a developer for developing an electrostatic latent image that are
excellent in production stability and storage stability of the
binder resin particles;
[0019] (5) A process for producing the toner for developing an
electrostatic latent image in a stable manner;
[0020] (6) A process for enabling stable formation of an image by
using the toner for developing an electrostatic latent image;
and
[0021] (7) An apparatus for enabling stable formation of an image
by using the toner for developing an electrostatic latent
image.
[0022] According to an aspect of the invention, the toner for
developing an electrostatic latent image contains a crystalline
resin having a melting point as a binder resin, and the toner
further contains at least one compound which is selected from (a)
an ester compound having an alkyl group having from 6 to 32 carbon
atoms and (b) a resin having a contact angle with water that is
smaller than that of the crystalline resin.
[0023] According to another aspect of the invention, the process
for producing a toner for developing an electrostatic latent image
contains the steps of: mixing by agitating a binder resin particle
dispersion and an aggregated particle stabilizer dispersion to
prepare an aggregated particle dispersion containing the binder
resin particles; and heating the aggregated particle dispersion to
a temperature higher than a melting point of a crystalline resin
contained in the binder resin to form toner particles.
[0024] According to a further aspect of the invention, a process
for forming an image contains the steps of: forming an
electrostatic latent image; developing the electrostatic latent
image with a developer to form a toner image; transferring the
toner image to a fixing substrate; and fixing the toner image to
the fixing substrate. In the process, the toner for developing an
electrostatic latent image described in the above aspect is used to
form the toner image.
BRIEF DESCRIPTION OF THE DRAWING
[0025] A preferred embodiment of the invention will be described in
detail based on the following figure, wherein:
[0026] FIG. 1 is a conceptual diagram showing an example of an
apparatus for forming an image for conducting the process for
forming an image according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0027] In the invention, the toner contains a crystalline resin
having a melting point as a binding resin and further contains at
least one of an ester compound having an alkyl group having from 6
to 32 carbon atoms and a resin having a contact angle with water
that is smaller than that of the crystalline resin, whereby it is
succeeded that the stability of the aggregated particles in the
dispersion is ensured, and the crystallinity of the binder resin is
maintained. The stability of the aggregated particles greatly
improves dispersibility of a colorant and a releasing agent in the
binder resin upon production of the toner by the aggregation and
coalescence process, and the maintenance of the crystallinity of
the binder resin enables maintenance of low temperature fixing
property, whereby a toner for developing an electrostatic latent
image that is excellent in low temperature fixing property and
color developing property can be provided.
[0028] In general, a crystalline resin suffers great decrease in
viscosity at a particular temperature because it has a melting
point, and the temperature difference from the start of thermal
activity of the resin molecules to the temperature range where
fixing can be conducted can be decreased, whereby an excellent
fixing property can be provided. On the other hand, a
noncrystalline resin suffers gradual decrease in viscosity to
provide a large temperature difference from the start of thermal
activity of the resin molecules at the glass transition point to
the temperature where fixing property can be conducted, and
therefore the low temperature fixing property cannot be
ensured.
[0029] According to the invention, the use of the crystalline resin
having a melting point is enabled to ensure an excellent low
temperature fixing property.
[0030] A crystalline resin having a melting point in a range of
from 45 to 110.degree. C. is suitable as the crystalline resin of
the invention to ensure the low temperature fixing property and the
storage stability of the toner. When the melting point is lower
than 45.degree. C., storage of the toner becomes difficult, and
when the melting point exceeds 110.degree. C., the effect of the
low temperature fixing property cannot be enjoyed. The melting
point of the crystalline resin is preferably in a range of from 50
to 100.degree. C., and more preferably in a range of from 55 to
90.degree. C. The melting point of the resin mentioned above was
obtained by the process shown in JIS K-7121.
[0031] It is advantageous that the toner of the invention has a
small particle diameter and a narrow particle size distribution,
and is suitably produced by an aggregation and coalescence process,
in which resin particles and colorant particles are aggregated and
coalesced. In the production of the aggregated particles in this
process, it is considered that the resin particles and colorant
particles dispersed and emulsified to a submicron size exhibiting
the Brownian motion form aggregated particles having a diameter of
about from 1 to 2 .mu.m due to the presence of an aggregating
agent, i.e., the so-called thermal motion aggregation occurs, and
furthermore, the aggregated particles are further aggregated to
adjust the particle size by heating the aggregated particle
dispersion, i.e., the so-called flow transportation aggregation
occurs.
[0032] Because the thermal motion aggregation and the flow
transportation aggregation do not simultaneously occur, it is
necessary to stably produce the aggregated particles having a
diameter of about from 1 to 2 .mu.m in order to finally obtain
particles having a narrow particle size distribution. When the
aggregation in the flow transportation aggregation region occurs
before sufficiently proceeding the thermal motion aggregation, the
aggregation proceeds with fine particles remaining, and thus it is
not preferred since the particle size distribution of the toner is
broadened.
[0033] The crystalline resin of the invention is hard to be
affected by the temperature below the melting point since a part or
the whole of the resin molecules is regularly arranged. Therefore,
there is a tendency that the stability of the aggregated particles
having a diameter of about from 1 to 2 .mu.m formed by thermal
motion aggregation becomes low. Furthermore, when an emulsifier,
such as a surfactant, is used in the stage of emulsification, the
stability of the aggregated particles is further lowered.
[0034] In the invention, an ester compound having an alkyl group
having from 6 to 23 carbon atoms is contained in the toner
containing a crystalline resin as a binder resin, so as to ensure
the stability of the aggregated particles with maintaining the low
temperature fixing property of the crystalline resin, whereby
improving the dispersibility of a colorant and a releasing agent in
the binder resin containing the crystalline resin. That is, it is
considered that the ester compound containing an alkyl group
improves the compatibility with the colorant and the releasing
agent by slightly dissolving with the crystalline part of the
crystalline resin, and the partial breakage of the crystallinity of
the crystalline resin improves the stability of the aggregated
particles formed by thermal motion aggregation, whereby the
dispersibility of the colorant and the releasing agent in the
binder resin containing the crystalline resin is improved. The
improvement in the dispersibility of the colorant and the releasing
agent greatly improves the coloring property and the fixing
property of the toner. Since the compound contains an alkyl group
to have low compatibility with the crystalline resin in a molten
state, it does not inhibit the crystallinity of the binder resin in
the steps of melting, cooling and integration, whereby the
advantage of the low temperature fixing property of the crystalline
resin can be enjoyed.
[0035] Furthermore, the combination use of the particular resin
(the resin having appropriate hydrophilicity) not only improves the
hydrophilicity of the various particles upon aggregation for
forming aggregated particles by an aggregation process, but also
makes particles having high hydrophilicity within the aggregated
particles be present on the surface of the aggregated particles due
to the difference of contact angles between the crystalline resin
particles and the particular resin particles, whereby the stability
of the aggregated particles is improved.
[0036] When the toner for developing an electrostatic latent image
of the invention satisfies the following property: when the
temperature is changed within a temperature range of about from 40
to 110.degree. C., the value of the storage elastic modulus (GL)
and a loss elastic modulus (GN) have an area which is changed by
10.sup.2 or more at a temperature of 10.degree. C., a necessary
viscosity can be obtained at the fixing temperature, and the low
temperature fixing property can be ensured. When the toner does not
satisfied such a property, the necessary viscosity for fixing
cannot be obtained, and thus the fixing temperature should be
increased, whereby the low temperature fixing property cannot be
obtained. The storage elastic modulus (GL) and the loss elastic
modulus (GN) are more preferably changed by 10.sup.2 or more at a
temperature difference of 10.degree. C. within a temperature range
of from 60 to 90.degree. C.
[0037] It is preferred that the toner for developing an
electrostatic latent image of the invention satisfies the following
equation (1):
0.ltoreq..vertline.log GL(Tm+20)-log GL(Tm+50).vertline..ltoreq.1.5
(1)
[0038] wherein Tm represents a melting point, GL(Tm+20) represents
a storage elastic modulus at Tm+20.degree. C., and GL(Tm+50)
represents a storage elastic modulus at Tm+50.degree. C. It is also
preferred that the toner of the invention satisfies the following
equation (2):
0.ltoreq..vertline.log GN(Tm+20)-log GN(Tm+50).vertline..ltoreq.1.5
(2)
[0039] wherein GN(Tm+20) represents a loss elastic modulus at
Tm+20.degree. C., and GN(Tm+50) represents a loss elastic modulus
at Tm+50.degree. C. In the foregoing equations, when the value
exceeds 1.5, it is not preferred since hot offset is liable to
occur upon high temperature fixing due to large dependence on the
fixing temperature.
[0040] When the toner for developing an electrostatic latent image
of the invention has a loss tangent tan .delta. at Tm+20.degree.
C., where Tm represents the melting point of the toner, satisfying
0.01.ltoreq.tan .delta..ltoreq.2 at an angular frequency of 1
rad/sec, excessive penetration into a fixing substrate, such as
paper, can be prevented, and simultaneously, the temperature region
where fixing can be conducted can be broadened. The loss tangent
tan .delta. preferably satisfies 0.1.ltoreq.tan .delta.<1.8.
[0041] The crystalline resin used as the binder resin in the
invention is not particularly limited in species as far as it has a
melting point in a range of from 45 to 110.degree. C. The melting
point of the crystalline resin is preferably in a range of from 50
to 100.degree. C., and more preferably in a range of from 55 to
90.degree. C. It is preferred that the toner containing the binder
resin of the invention contains such a crystalline resin that can
satisfy the following property: when the temperature is changed
within a temperature range of about from 40 to 110.degree. C., the
value of the storage elastic modulus (GL) and a loss elastic
modulus (GN) have an area which is changed by 10.sup.2 or more at a
temperature of 10.degree. C. The storage elastic modulus (GL) and
the loss elastic modulus (GN) are more preferably changed by
10.sup.2 or more at a temperature difference of 10.degree. C.
within a temperature range of from 60 to 90.degree. C.
[0042] A monomer constituting the crystalline resin of the
invention is not particularly limited, and specific examples
thereof include vinyl series resins using the following
monomers:
[0043] (1) A dicarboxylic acid having a long-chain alkyl group,
such as adipic acid, pimelic acid, suberic acid, azelaic acid,
sebacic acid, dodecanoic diacid and tridecanoic diacid;
[0044] (2) A (meth)acrylate having a long-chain alkyl or alkenyl
group, such as amyl (meth)acrylate, hexyl (meth)acrylate, heptyl
(meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl
(meth)acrylate, undecyl (meth)acrylate, tridecyl (meth)acrylate,
myristyl (meth)acrylate, cetyl (meth)acrylate, stearyl
(meth)acrylate, oleyl (meth)acrylate and behenyl
(meth)acrylate.
[0045] A polyester resin using a diol having a long-chain alkyl or
alkenyl group, such as butanediol, pentanediol, hexanediol,
heptanediol, octanediol, nonanediol, decanediol and butyl
alcohol.
[0046] The crystalline resin of the invention may contain, in
addition to the foregoing monomers, a compound containing an alkyl
group, an alkenyl group and an aromatic ring having a shorter chain
for adjusting the melting point and the molecular weight. Specific
examples thereof include the following:
[0047] (1) For the case where the monomer is a dicarboxylic acid,
an alkyl dicarboxylic acid, such as succinic acid, malonic acid and
oxalic acid, an aromatic dicarboxylic acid, such as phthalic acid,
isophthalic acid, terephthalic acid, homo phthalic acid,
4,4-bibenzoic acid, 2,6-naphthalenedicarboxylic acid and
1,4-naphthalenecarboxilic acid; and a nitrogen-containing aromatic
dicarboxylic acid, such as dipicolinic acid, dinicotinic acid,
quinolinic acid and 2,3-pyrazinedicarboxylic acid;
[0048] (2) For the case where the monomer is a diol, a diol having
a short-chain alkyl group, such as ethylene grycol, propylene
grycol; and
[0049] (3) As a vinyl series monomer having a short-chain alkyl
group, a (meth)acrylate of a short-chain alkyl or alkenyl, such as
methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate
and a butyl (meth)acrylate, a vinyl nitrile, such as acrylonitrile
and methacrylonitrile, a vinyl ether, such as vinyl methyl ether
and vinyl isobutyl ether, a vinyl ketone, such as vinyl methyl
ketone, vinyl ethyl ketone and vinyl isopropenyl ketone, and an
olefin, such as ethylene, propylene, butadiene and isoprene.
[0050] These monomers may be used singly or in combination of two
or more of them.
[0051] Since the crystalline resin is poor in emulsion
dispersibility by its nature, an emulsifier, such as a surfactant,
is added. The use of an emulsifier is preferably suppressed because
the addition of an emulsifier brings about problems of decrease in
charge amount of the particles and prolongation of a washing step
for preventing the decrease in charge amount. In the invention, in
the case where a sulfonyl group-containing monomer is mixed upon
polymerization of the crystalline resin, the dispersion stability
of the aggregated particles can be maintained even when the use
amount of the emulsifier is decreased. The species of the sulfonyl
group-containing monomer is not particularly limited as far as it
can be copolymerized. Specific examples thereof include, for the
case where the resin is a polyester, a dicarboxylic acid compound
having a sulfonyl group directly substituted on the aromatic ring,
such as sodium sulfonylterephthalate and sodium
3-sulfonylisophthalate, and for the case where the resin is a vinyl
series resin, a sulfonyl group-substituted aromatic vinyl compound,
such as a styrene derivative having a sulfonyl group at one of the
o-, m- and p-positions and a sulfonyl group-containing
vinylnaphthalene.
[0052] The crystalline resin particle dispersion in the invention
is liable to cause aggregation by thermal motion aggregation. Even
though the aggregation can be suppressed by adding a dispersant or
an emulsifier, there are problems of decrease in charge amount of
the particles and prolongation of a washing step for preventing the
decrease in charge amount as described in the foregoing. The resin
particle dispersion is preferably stored at a temperature of
40.degree. C. or less, and more preferably 20.degree. C. or less.
When it is stored at a temperature exceeding 40.degree. C., it is
necessary to re-disperse the aggregated particles upon dispersion,
and therefore it is not preferred since the dispersion uniformity
cannot be ensured, and extra energy for agitating the aggregated
particles becomes necessary.
[0053] A crosslinking agent may be added to the binder resin of the
invention depending on necessity for preventing hot offset upon
fixing in a high temperature region. Specific examples of the
crosslinking agent include the following:
[0054] (1) An aromatic polyvinyl compound, such as divinylbenzene
and divinylnaphthalene;
[0055] (2) A polyvinyl ester of an aromatic polyvalent carboxylic
acid, such as divinyl phthalate, divinyl isophthalate, divinyl
terephthalate, divinyl homophthalate, divinyl or trivinyl
trimesate, divinyl naphthalenedicarboxylate and divinyl
biphenylcarboxylate;
[0056] (3) A divinyl ester of a nitrogen-containing aromatic
compound, such as divinyl pyridinecarboxylate;
[0057] (4) An unsaturated heterocyclic compound, such as pyrrole
and thiophene;
[0058] (5) A vinyl ester of a carboxylic acid of an unsaturated
heterocyclic compound, such as vinyl pyromucinate, vinyl
furancarboxylate, vinyl pyrrole-2-carboxylate and vinyl
thiophenecarboxylate;
[0059] (6) A (meth)acrylate of a linear polyhydric alcohol, such as
butanediol methacrylate, hexanediol acrylate, octanediol
methacrylate, decanediol acrylate and dodecanediol
methacrylate;
[0060] (7) A (meth)acrylate of a branched or substituted polyhydric
alcohol, such as neopentyl glycol dimethacrylate and
2-hydroxy-1,3-diacryloxypropane;
[0061] (8) Polyethylene glycol di(meth)acrylate and polypropylene
polyethylene glycol di(meth)acrylate; and
[0062] (9) A polyvinyl ester of a polyvalent carboxylic acid, such
as divinyl succinate, divinyl fumarate, vinyl or divinyl maleate,
divinyl diglycolate, vinyl or divinyl itaconate, divinyl
acetonedicarboxylate, divinyl glutarate, divinyl
3,3'-thiodipropionate, divinyl or trivinyl trans-aconitate, divinyl
adipate, divinyl pimelate, divinyl suberate, divinyl azelate,
divinyl sebacate, divinyl didodecanate and divinyl brassylate.
[0063] Particularly in the case where the resin is a polyester,
such a method may be employed in that an unsaturated polycarboxylic
acid, such as fumaric acid, maleic acid, itaconic acid and
trans-aconitic acid, is copolymerized in the polyester, and then
crosslinking is effected by using the multiple bond parts in the
resin or other vinyl series compounds.
[0064] In the invention, these crosslinking agents may be used
singly or in combination of two or more of them.
[0065] The crosslinking method may be such a method that the
monomer is with the crosslinking agent to effect crosslinking, or
in alternative, such a method that the unsaturated bond parts are
left in the resin, and after polymerizing the resin or after
producing the toner, crosslinking is effected by a crosslinking
reaction of the unsaturated bond parts.
[0066] In the case where the binder resin used in the toner of the
invention is polyester, the monomer may be polymerized by
condensation polymerization.
[0067] As a catalyst for condensation polymerization, known
compounds may be used, and specific examples thereof include
titanium tetrabutoxide, dibutyltin oxide, germanium dioxide,
antimony trioxide, tin acetate, zinc acetate and tin disulfide.
[0068] In the case where the binder resin used in the toner of the
invention is a vinyl series resin, the monomer may be polymerized
by radical polymerization.
[0069] An initiator for radical polymerization is not particularly
limited as far as it can initiate emulsion polymerization. Specific
examples thereof include the following:
[0070] (1) A peroxide, such as hydrogen peroxide, acetyl peroxide,
cumyl peroxide, tert-butyl peroxide, propyonyl peroxide, benzoyl
peroxide, chlorobenzoyl peroxide, dichlorobenzoyl peroxide,
bromomethylbenzoyl peroxide, lauroyl peroxide, ammonium persulfate,
sodium persulfate, potassium persulfate, diisopropyl
peroxycarbonate, tetralin hydroperoxide,
1-phenyl-2-methylpropyl-1-hydroperoxide, tert-butyl
triphenylperacetate hydroperoxide, tert-butyl performate,
tert-butyl peracetate, tert-butyl perbenzoate, tert-butyl
phenylperacetate, tert-butyl methoxyperaceate and tert-butyl
N-(3-toluyl)percarbamate;
[0071] (2) An azo compound, such as 2,2'-azobispropane,
2,2'-dichloro-2,2'-azobispropane, 1,1'-azo(methylethyl) diacetate,
2,2'-azobis(2-amidinopropane)hydrochloride,
2,2'-azobis(2-amidinopropane) nitrate, 2,2'-azobisisobutane,
2,2'-azobisisobutylamide, 2,2'-azobisisobutylonitrile, methyl
2,2'-azobis-2-methylpropionate, 2,2'-dichloro-2,2'-azobisbutane,
2,2'-azobis-2-methylbutylonitrile, dimethyl 2,2'-azobisisobutylate,
1,1'-azobis(sodium 1-methylbutylonitrile-3-sulfonate),
2-(4-methylphenylazo)-2-methylmalonod- initrile,
4,4'-azobis-4-cyanovaleric acid, 3,5-dihydroxymethylphenylazo-2--
methylmalonodinitrile, 2-(4-boromophenylazo)-2-allylmalononitrile,
2,2'-azobis-2-methylvaleronitrile, dimethyl
4,4'-azobis-4-cyanovalarate, 2,2'-azobis-2,4-dimethylvaleronitrile,
1,1'-azobiscyclohexanenitrile, 2,2'-azobis-2-propylbutylonitrile,
1,1'-azobis-1-chlorophenylethane,
1,1'-azobis-1-cyclohexanecarbonitrile,
1,1'-azobis-1-cycloheptanenitrile, 1,1'-azobis-1-phenylethane,
1,1'-azobiscumene, ethyl 4-nitrophenylazobenzylcyanoacetate,
phenylazodiphenylmethane, phenylazotriphenylmethane,
4-nitrophenylazotriphenylmethane, 1,1'-azobis-1,2-diphenylethane,
poly(bisphenol A-4,4-azobis-4-cyanopentan- oate) and
poly(tetraethylene glycol-2,2'-azobisisobutylate); and
[0072] (3) 1,4-Bis(pentaethylene)-2-tetrazene and
1,4-dimethoxycarbonyl -1,4-diphenyl-2-tetrazene.
[0073] The polymerization initiators may also be used as an
initiator for the crosslinking reaction in the crosslinking
step.
[0074] As the colorant used in the toner of the invention, at least
one kind selected from a cyan pigment, a magenta pigment and a
yellow pigment may be used. The pigments may be used singly or as a
mixture of two or more pigments of the same series. Two or more
pigments of different series may also be used as a mixture.
Specific examples of the colorant include various pigments, such as
Chrome Yellow, Hansa Yellow, Benzidine Yellow, Suren Yellow,
Quinoline Yellow, Permanent Orange GTR, Pyrazolone Orange, Vulkan
Orange, Watchyoung Red, Permanent Red, Brilliant Carmine 3B,
Brilliant Carmine 6B, Du Pont Oil Red, Pyrazolone Red, Lithol Red,
Rhodamine B Lake, Lake Red C, Rose Bengal, Aniline Blue,
Ultramarine Blue, Calco Oil Blue, Methylen Blue Chloride,
Phthalocyanine Blue, Phthalocyanine Green and Malachite Green
Oxalate; and various dyes, such as acridine series, xanthene
series, azo series, benzoquinone series, azine series,
anthraquinone series, dioxane series, thiazine series, azomethine
series, indigo series, thoindigo series, phthalocyanine series,
aniline black series, polymethine series, triphenylmethane series,
diphenylmethane series, thiazole series and xanthene series. A
black pigment or a black dye, such as carbon black, may be added to
the colorant in such an extent that the transparency is not
impaired.
[0075] A releasing agent may be added to the toner of the invention
depending on necessity.
[0076] Specific examples of the releasing agent include a low
molecular weight polyolefin, such as polyethylene, polypropylene
and polybutene; a silicone compound having a softening point upon
heating; an aliphatic amide, such as oleic amide, erucic amide,
recinoleic amide and stearic amid; vegetable wax, such as carnauba
wax, rice wax, candelilla wax, Japan wax and jojoba oil; animal
wax, such as yellow beeswax; and mineral and petroleum wax, such as
montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax
and Fischer-Tropsch wax. The releasing agents may be used singly or
in combination of two or more of them.
[0077] The addition amount of the releasing agent is preferably in
a range of from 0.5 to 50% by weight, more preferably from 1 to 30%
by weight, and further preferably from 5 to 15% by weight. When the
addition amount is less than 0.5% by weight, no effect of addition
of the releasing agent is obtained. When it exceeds 50% by weight,
the charging property is adversely affected, and the toner is
liable to be broken in a developing unit to make the releasing
agent be spent to the carrier, whereby not only adverse effects,
such as decrease in charging, occur, but also in the case where a
color toner is used, appearance on the image surface upon fixing is
liable to be insufficient, and thus there is a possibility that the
releasing agent remains in the image to deteriorate the
transparency.
[0078] The ester compound used in the invention has an alkyl group
having from 6 to 32 carbon atoms, and a compound having a molecular
weight of about from 200 to 1,500 is suitably used. When the number
of carbon atoms of the alkyl group is less than 5, the
hydrophilicity of the ester compound becomes too high to make the
ester compound be hydrophilic, and it is not dissolved in the
crystalline resin. When the number of carbon atoms is 33 or more,
it cannot migrate in the crystalline resin, and thus the dispersion
stability of the aggregated particles cannot be ensured. When the
molecular weight of the ester compound is less than 200, the
particle size distribution of the aggregated particles is liable to
be broadened since it is difficult to be compatible with the
crystalline resin owing to the large difference in viscosity. When
the molecular weight exceeds 1,500, an impurity, such as an isomer,
is liable to be mixed in the ester compound, and it is not
preferred since the controllability is decreased. A polymer having
a large number of carbon atoms, such as polyester, is poor in
orientation property and cannot be exhibit the addition effect of
the ester compound of the invention. A preferred example of the
ester compound of the invention is one having from 10 to 24 carbon
atoms and a molecular weight in a range of from 300 to 700.
[0079] Specific examples of the ester compound used in the
invention include the following. These compounds may be used singly
or in combination of two or more of them.
[0080] (1) An ester of a higher fatty acid and a higher alcohol,
such as stearyl stearate and behenyl behenate;
[0081] (2) An ester of a higher fatty acid and a monohydric or
polyhydric lower alcohol, such as butyl stearate, propyl oleate,
monostearic glyceride, distearic glyceride and pentaerythritol
tetrabehenate;
[0082] (3) An ester of a higher fatty acid and a polyhydric
alcohol, such as diethylene glycol monostearate, dipropylene glycol
distearate, distearic diglyceride and tetrastearic
triglyceride;
[0083] (4) A sorbitan higher fatty acid ester, such as sorbitan
monostearate; and
[0084] (5) A cholesterol higher fatty acid ester, such as
cholesteryl stearate.
[0085] In the toner for developing an electrostatic latent image
according to the invention, the resin having a contact angle with
water that is smaller than the crystalline resin forms a difference
in contact angle with water from the crystalline resin. The
difference in contact angle with water between them is preferably
about 3.degree. or more, more preferably 5.degree. or more, further
preferably 10.degree. or more, and particularly preferably
15.degree. or more. In the case where the difference in contact
angle with water is less than 3.degree., there are cases where the
aggregation property of the crystalline resin is deteriorated upon
production of the toner by the aggregation process.
[0086] The resin having a contact angle with water that is smaller
than that of the crystalline resin preferably has a contact angle
with water in the range of about from 30 to 120.degree., more
preferably from 50 to 120.degree., and further preferably from 70
to 120.degree.. When a resin having a contact angle with water of
less than 30.degree. is used, the charging property of the toner is
liable to be affected by humidity, and thus there are cases where
the environmental stability becomes poor. When a binding resin
having a contact angle with water exceeding 120.degree. is used,
the adhesion property with paper upon fixing is deteriorated, and
thus there are cases where a toner of poor fixing property is
obtained. Similarly, the crystalline resin preferably has a contact
angle with water within the ranges described in the foregoing.
[0087] The contact angle with water used herein is measured in the
following manner. Powder of the resin to be measured is molded
under pressure of about 20 ton/cm.sup.2 for 30 seconds to produce a
resin plate. Pure water is placed in a syringe, and a water droplet
of a prescribed size is prepared. The resin plate is slowly lifted
up until the resin plate is in contact with the water droplet, and
after the contact, the resin plate is then taken down. A contact
angle formed between the tangent line at an edge of the droplet and
the surface of the resin plate is measured. The measured contact
angle is designated as the contact angle with water referred
herein. The measurement of the contact angle can be conducted by
using a commercially available contact angle meter (Type CA-DTA,
produced by Kyowa Interface Science Co., Ltd.).
[0088] When the resin having a contact angle with water that is
smaller than that of the crystalline resin is a resin having a
glass transition point that is lower than the melting point of the
crystalline resin, a toner having good reproducibility is obtained
because upon formation of the aggregated particles by the
aggregation process, the viscosity of the particular resin is
lowered at a temperature over the glass transition point to
increase the aggregation force among the particles, and thus the
stability, the particle size and the particle size distribution of
the aggregated particles can be easily controlled.
[0089] Specific examples of the resin having a contact angle with
water that is smaller than that of the crystalline resin include a
homopolymer or a copolymer of a styrene compound, such as styrene,
parachlorostyrene and .alpha.-methylstyrene (a styrene series
resin); a homopolymer or a copolymer of an ester having a vinyl
group, such as methyl acrylate, ethyl acrylate, n-propyl acrylate,
n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl
methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl
methacrylate and 2-ethylhexyl methacrylate (a vinyl series resin);
a homopolymer or a copolymer of a vinyl nitrile, such as
acrylonitrile and methacrylonitrile (a vinyl series resin); a
homopolymer or a copolymer of a vinyl ether, such as vinyl methyl
ether and vinyl isobutyl ether (a vinyl series resin); a
homopolymer or a copolymer of a vinyl ketone, such as vinyl methyl
ketone, vinyl ethyl ketone and vinyl isopropenyl ketone (a vinyl
series resin); a homopolymer or a copolymer of an olefin, such as
ethylene, propylene, butadiene and isoprene (an olefin series
resin); a non-vinyl condensation resin, such as an epoxy resin, a
polyester resin, a polyurethane resin, a polyamide resin, a
cellulose resin and a polyether resin; and a graft polymer of the
non-vinyl condensation resin and the vinyl series monomer. The
resins may be used singly or in combination of two or more of
them.
[0090] The proportion of the resin with respect to the crystalline
resin is preferably from 1 to 50%, more preferably from 3 to 40%,
and further preferably from 5 to 30%. When the proportion is less
than 1%, there are cases where the hydrophilicity of the aggregated
particles upon production of the toner by the aggregation process
becomes insufficient, and it is not preferred since the stability
is deteriorated. When it exceeds 50%, the effect of the crystalline
resin upon fixing is difficult to be exhibited, and it is not
preferred since there are cases where the low temperature fixing
property is deteriorated.
[0091] In order to obtain high image quality, the volume average
particle diameter of the toner of the invention is preferably
adjusted to the range of from 3 to 10 .mu.m. When it exceeds 10
.mu.m, the reproducibility of thin lines in the developing step
becomes poor, and thus the image quality is deteriorated. When it
is lower than 3 .mu.m, it is not preferred since the service life
of the developer is shortened. The volume average particle diameter
of the toner of the invention is more preferably in the range of
from 4 to 7 .mu.m.
[0092] Process for Producing Toner for Developing Electrostatic
Latent Image
[0093] The toner for developing an electrostatic latent image
according to the invention is preferably produced in the following
aggregation and coalescence process. A resin is agitated and
dispersed in a dispersion to prepare a resin particle dispersion,
or in alternative, a resin particle dispersion is produced by
emulsion polymerization. The resin particle dispersion is mixed
with a dispersion of an aggregated particle stabilizer and
dispersions of a pigment and a releasing agent to effect hetero
aggregation, and then the crystalline resin is melted to integrate
the particles to obtain toner particles. The colorant may be
previously contained in the resin particles. This process is
preferred from the standpoint of obtaining the foregoing effects.
The toner for developing an electrostatic latent image according to
the invention may also be produced by a dissolution and suspension
process and a suspension polymerization process.
[0094] The aggregation and coalescence process of the invention
contains a step of mixing at least a resin particle dispersion and
a dispersion of an aggregated particle stabilizer, as well as,
depending on necessity, a colorant dispersion and a releasing agent
dispersion, so as to aggregate resin particles to form aggregated
particles, whereby an aggregated particle dispersion is prepared
(an aggregating step), and a step of heating the aggregated
particles to form toner particles (a coalescing step).
[0095] In the aggregating step, the hetero aggregation is conducted
to form the aggregated particles by adding an ionic surfactant
having a polarity different from that of the aggregated particles
and a compound having a charge of one or more valent, such as a
metallic salt, so as to stabilize the aggregated particles and to
control the particle size and the particle size distribution.
[0096] In the coalescing step, the aggregated particles is heated
to a temperature higher than the melting point of the crystalline
resin contained in the aggregated particles, so as to obtain the
toner particles.
[0097] The coalesced particles obtained by coalescing in the
coalescing step are present in an aqueous medium in the form of a
colored particle dispersion. The dispersion is washed to remove the
colored particles from the aqueous medium and to remove impurities
formed in the respective steps, followed by drying, so as to obtain
the toner particles.
[0098] In the washing step, acidic or basic washing water is added
in an amount of several times the colored particles, and after
agitation, a solid content is obtained by filtration. Pure water is
added to the solid content in an amount of several times the solid
content, and after agitation, filtration is conducted. The
foregoing operation is repeated by several times until the pH of
the filtrate after filtration becomes about 7 to obtain the colored
particles.
[0099] In the drying step, the colored particles obtained in the
washing step are dried at a temperature below the melting point of
the colored particles. At this time, depending on necessity, dried
air is circulated, or heating is effected under vacuum.
[0100] In order to stabilize the resin particle dispersion, the
colorant dispersion and the releasing agent dispersion used in the
invention, the resin particle dispersion of the invention can be
used as it is. However, in the case where the colorant dispersion
and the releasing agent dispersion are difficult to be dispersed as
they are, or in the case where the stability of the resin particle
dispersion is to be maintained with the lapse of time, a slight
amount of a surfactant may be employed.
[0101] Examples of the surfactant include an anionic surfactant,
such as a sulfate series, a sulfonate series, a phosphate series
and a soap series; a cationic surfactant, such as an amine salt
type and a quaternary ammonium salt type; and a nonionic
surfactant, such as a polyethylene glycol series, an alkylphenol
ethylene oxide adduct series and a polyhydric alcohol series. Among
these, an ionic surfactant is preferred, and an anionic surfactant
and a cationic surfactant are more preferred.
[0102] In the production process of the toner of the invention, a
cationic surfactant is advantageous as a surfactant for dispersing
the releasing agent because an anionic surfactant generally has a
high dispersion power and is excellent in dispersion of the resin
particles and the colorant.
[0103] A nonionic surfactant is preferably used in combination with
the anionic surfactant or the cationic surfactant. The foregoing
surfactants may be used singly or in combination of two or more of
them. Specific examples of the anionic surfactant include a fatty
acid soap, such as potassium laurate, sodium oleate and sodium
castor oil; a sulfate, such as octyl sulfate, lauryl sulfate,
lauryl ether sulfate and nonyl phenyl ether sulfate; a sulfonate,
lauryl sulfonate, dodecylbenzene sulfonate, a sodium
alkylnaphthalene sulfonate, e.g., triisopropylnaphthalene sulfonate
and dibutylnaphthalene sulfonate, a naphthalene sulfonate formalin
condensate, monooctyl sulfosuccinate, dioctyl sulfosuccinate,
lauric amide sulfonate and oleic amide sulfonate; a phosphate, such
as lauryl phosphate, isopropyl phosphate and nonyl phenyl ether
phosphate; a dialkyl sulfosuccinate, such as sodium dioctyl
sulfosuccinate; and a sulfosuccinate, such as disodium lauryl
sulfosuccinate.
[0104] Specific examples of the cationic surfactant include an
amine salt, such as laurylamine hydrochloride, stearylamine
hydrochloride, oleylamine acetate, stearylamine acetate and
stearylaminopropylamine acetate; and a quaternary ammonium salt,
such as lauryltrimethylammonium chloride, dilauryldimethylammonium
chloride, distearylammonium chloride, distearyldimethylammonium
chloride, lauryldihydroxyethylmethylammonium chloride,
oleylbispolyoxyethylenemethylammonium chloride,
lauroylaminopropyldimethylethylammonium ethosulfate,
lauroylaminopropyldimethylhydroxyethylammonium perchlorate,
alkylbenzenedimethylammonium chloride and alkyltrimethylammonium
chloride.
[0105] Specific examples of the nonionic surfactant include an
alkyl ether, such as polyoxyethylene octyl ether, polyoxyethylene
lauryl ether, polyoxyethylene stearyl ether and polyoxyethylene
oleyl ether; an alkyl phenyl ether, such as polyoxyethylene octyl
phenyl ether and polyoxyethylene nonyl phenyl ether; an alkyl
ester, such as polyoxyethylene laurate, polyoxyethylene stearate
and polyoxyethylene oleate; an alkyl amine, such as polyoxyethylene
laurylamino ether, polyoxyethylene stearylamino ether,
polyoxyethylene oleylamino ether, polyoxyethylene soy bean amino
ether and polyoxyethylene beef tallow amino ether; an alkyl amide,
such as polyoxyethylene lauric amide, polyoxyethylene stearic amide
and polyoxyethylene oleic amide; a vegetable oil ether, such as
polyoxyethylene castor oil ether and polyoxyethylene colza oil
ether; an alkanol amide, such as lauric diethanol amide, stearic
diethanol amide and oleic diethanol amide; and a sorbitan ester
ether, such as polyoxyethylene sorbitan monolaurate,
polyoxyethylene sorbitan monoparmitate, polyoxyethylene sorbitan
monostearate and polyoxyethylene sorbitan monooleate.
[0106] The content of the surfactant in the dispersion may be such
an extent that does not impair the invention, and is generally a
small amount. Specifically, in the case of the resin particle
dispersion, it is suitably in the range of from 0.01 to 1% by
weight, preferably from 0.02 to 0.5% by weight, and more preferably
from 0.1 to 0.2% by weight. When the content of the surfactant is
less than 0.01% by weight, there are cases where aggregation occurs
particularly in the case where the pH of the resin particles
dispersion is not sufficiently basic.
[0107] The content of the surfactant in the colorant dispersion and
the releasing agent dispersion is suitably in the range of from
0.01 to 10% by weight, preferably from 0.1 to 5% by weight, and
more preferably from 0.5 to 2% by weight. When the content of the
surfactant is less than 0.01% by weight, scattering occurs in the
stability among the particles upon aggregation to cause a problem
of isolation of particular particles. When it exceeds 10% by
weight, the particle size distribution is broadened, and the
particle diameter is difficult to be controlled. Therefore, both
the cases are not preferred.
[0108] To the toner of the invention, particles of other
components, such as an internal additive, a charge controlling
agent, inorganic particles, organic particles, a lubricant and an
abrasive, may be added, in addition to the binder resin, the
colorant and the releasing agent, depending on necessity.
[0109] The internal additive may be used as far as it does not
impair the charging property of the toner characteristics, and
examples of which include a metal, an alloy and a compound
containing a metal, such as ferrite, magnetite, reduced iron,
cobalt, manganese and nickel.
[0110] The charge controlling agent is not particularly limited,
and in the case where it is used in a color toner, colorless or
leucocratic ones are preferred. Examples thereof include a
quaternary ammonium salt compound, nigrosine series compound, a dye
containing a complex of aluminum, iron or chromium, and a
triphenylmethane series pigment.
[0111] Examples of the inorganic particles include all particles
that are ordinarily used as an external additive to the toner
surface, such as silica, titania, calcium carbonate, magnesium
carbonate, tricalcium phosphate and cerium oxide.
[0112] Examples of the organic particles include particles that are
ordinarily used as an external additive to the toner surface, such
as a vinyl series resin, a polyester resin and a silicone resin.
The inorganic particles and the organic particles may also be used
as a fluidity assistant and a cleaning assistant.
[0113] Examples of the lubricant include a fatty acid amide, such
as ethylenebisstearic amide and oleic amide, and fatty acid
metallic salt, such as zinc stearate and calcium stearate.
[0114] Examples of the abrasive include silica, alumina and cerium
oxide described in the foregoing.
[0115] Upon mixing the binder resin, the colorant and the releasing
agent, the content of the colorant in the toner may be 50% by
weight or less, and preferably in the range of from 2 to 40% by
weight.
[0116] The contents of the other components may be such an extent
that does not impair the effect of the invention, and are generally
slight amounts. Specifically, it is generally in the range of from
0.01 to 5% by weight, and preferably from 0.5 to 2% by weight.
[0117] An aqueous medium, for example, is used as the dispersion
medium of the resin particle dispersion, the colorant dispersion,
the releasing agent dispersion and other component dispersions of
the invention.
[0118] Examples of the aqueous medium include water, such as
distilled water and ion exchanged water, and an alcohol. These may
be used singly or in combination of two or more of them.
[0119] In the preparation step of the aggregated particle
dispersion in the invention, it is preferred to add an aggregating
agent, so as to accelerate and stabilize the aggregation of the
particles, and to obtain the aggregated particles having a narrower
particle size distribution.
[0120] As the aggregating agent, a compound having one or more
valent charge is preferred, and specific examples thereof include a
water soluble surfactant, such as an ionic surfactant and a
nonionic surfactant; an acid, such as hydrochloric acid, sulfuric
acid, nitric acid, acetic acid and oxalic acid; a metallic salt of
an inorganic acid, such as magnesium chloride, sodium chloride,
aluminum sulfate, calcium sulfate, ammonium sulfate, aluminum
nitrate, silver nitrate, copper sulfate and sodium carbonate; a
metallic salt of a fatty acid or an aromatic acid, such as sodium
acetate, potassium formate, sodium oxalate, sodium phthalate and
potassium salicylate; a metallic salt of a phenol, such as sodium
phenolate; a metallic salt of an amino acid; and an inorganic acid
salt of a fatty or aromatic amine, such as triethanolamine
hydrochlorate and aniline hydrochlorate.
[0121] A metallic salt of an inorganic acid is preferred from the
standpoint of performance and use with consideration of the
stability of the aggregated particles, the thermal stability and
the time-lapse stability of the aggregating agent, and the removal
of the aggregating agent upon washing.
[0122] The addition amount of the aggregating agent may be a small
amount, while depending on the valence number of charge, and may be
3% by weight or less for monovalence, 1% by weight or less for
divalence, and 0.5% by weight or less for trivalence. Since it is
preferred that the amount of the aggregated agent is as small as
possible, a compound having a larger valence is preferred.
[0123] The surface area of the toner for developing an
electrostatic latent image according to the invention is not
particularly limited, and no problem occurs when it is in the range
that is generally used in a toner. Specifically, the surface area
measured by the BET method is suitably from 0.5 to 10 m.sup.2/g,
preferably from 1.0 to 7 m.sup.2/g, and more preferably from 1.2 to
5 m.sup.2/g.
[0124] Inorganic particles, such as silica, alumina, titania and
calcium carbonate, and resin particles, such as a vinyl series
resin, a polyester resin and silicone resin, may be added to the
surface of the toner for developing an electrostatic latent image
according to the invention by mixing under application of a
shearing force in a dry state. The inorganic particles and the
resin particles function as a fluidity assistant or a cleaning
assistant.
[0125] The absolute value of the charge amount of the toner for
developing an electrostatic latent image is suitably in the range
of from 10 to 40 .mu.C/g, and preferably from 15 to 35 .mu.C/g.
When the absolute value of the charge amount is less than 10
.mu.C/g, background stain is liable to occur, and when it exceeds
40 .mu.C/g, decrease in image density is liable to occur.
[0126] The ratio of the charge amount in the summer season and the
charge amount in the winter season of the toner for developing an
electrostatic latent image is suitably in the range of from 0.5 to
1.5, and preferably from 0.7 to 1.3. When the ratio is outside the
range, it is not preferred from the practical standpoint since the
environmental dependency of the toner becomes large to lack the
stability in charging.
[0127] Developer for Developing Electrostatic Latent Image
[0128] The developer for developing an electrostatic latent image
according to the invention is not particularly limited except that
the toner for developing an electrostatic latent image according to
the invention is contained, and an appropriate component
composition may be employed depending on purpose.
[0129] The developer for developing an electrostatic latent image
according to the invention may be prepared as a one-component
developer using the toner for developing an electrostatic latent
image solely, or as a two-component developer using the toner and a
carrier in combination.
[0130] The carrier is not particularly limited, and the known
carriers may be employed. For example, the known carrier, such as
the resin coated carriers described in Japanese Patent Laid-Open
Nos.39879/1987 and 11461/1981 may be used.
[0131] Specific examples of the carrier include the following resin
coated carriers. Examples of core particles of the carrier include
ordinary iron powder, and molded particles of ferrite and
magnetite, and the average particle diameter thereof is about from
30 to 200 .mu.m.
[0132] Examples of the resin coated on the core particles include a
homopolymer of a monomer or a copolymer formed from two or more
monomers, such as a styrene compound, such as styrene,
p-chlorostyrene and .alpha.-methylstyrene, an .alpha.-methylene
fatty acid monocarboxylate, such as methyl acrylate, ethyl
acrylate, n-propyl acrylate, lauryl acrylate, 2-ethylhexyl
acrylate, methyl methacrylate, n-propyl methacrylate, lauryl
methacrylate and 2-ethylhexyl methacrylate, a nitrogen-containing
acrylic compound, such as dimethylaminoethyl methacrylate, a vinyl
nitrile, such as acrylonitrile and methacrylonitrile, a
vinylpyridine, such as 2-vinylpyridine and 4-vinylpyridine, a vinyl
ether, such as vinyl methyl ether and vinyl isobutyl ether, a vinyl
ketone, such as vinyl methyl ketone, vinyl ethyl ketone and vinyl
isopropenyl ketone, an olefin, such as ethylene and propylene, and
a vinyl series fluorine-containing monomer, such as vinylidene
fluoride, tetrafluoroethylene and hexafluoropropylene; a silicone,
such as methylsilicone and methylphenylsilicone; a polyester
containing bisphenol and glycol; an epoxy resin; a polyurethane
resin; a polyamide resin; a cellulose resin; a polyether resin; and
a polycarbonate resin. These resins may be used singly or in
combination of two or more of them. The amount of the coated resin
is suitably in the range of from 0.1 to 10 parts by weight based on
the core particles, and preferably from 0.5 to 3.0 parts by
weight.
[0133] In the production of the carrier, a heating kneader, a
heating Henschel mixer and an UM mixer may be used, and a heating
fluidized rolling bed and a heating kiln may also be used depending
on the amount of the coating resin.
[0134] The mixing ratio of the toner and the carrier in the
developer for developing an electrostatic latent image is not
particularly limited and may be appropriately selected depending on
purpose.
[0135] Process for Forming Image
[0136] The process for forming an image according to the invention
contains the step of forming an electrostatic latent image, the
step of forming a toner image, the transferring step and the fixing
step. The respective steps for forming an image are ordinary
processes and described, for example, in Japanese Patent Laid-Open
Nos. 40868/1981 and 91231/1974, and they can be applied to a known
apparatus for forming an image, such as a duplicator and a
facsimile machine.
[0137] In the formation of an electrostatic latent image, an
electrostatic latent image is formed on an electrostatic latent
image holding member. In the formation of a toner image, the
electrostatic latent image is developed with a developer layer on a
developer holding member to form a toner image. The developer layer
is not particularly limited as far as it contains the developer for
developing an electrostatic latent image according to the
invention. In the transferring step, the toner image is transferred
to a fixing substrate. In the fixing step, the toner image
transferred to the fixing substrate is fixed on the fixing
substrate, such as paper by heating with a fixing member.
[0138] The characteristic features of the process for forming an
image according to the invention are that the fixing temperature of
a belt type fixing unit and a roll type fixing unit can be low by
using the toner for developing an electrostatic latent image
according to the invention, excellent in low temperature fixing
property, so as to enable high speed fixing, and an energy saving
effect and an effect of shortening the warm-up time can be
obtained. Particularly, in the process for forming an image
employing a belt type fixing unit having low heating performance
for fixing, it is advantageous since good image quality can be
obtained without forming background fogging and cold offset.
[0139] Apparatus for Forming Image
[0140] An example of an apparatus for forming an image according to
the invention is shown in FIG. 1. The apparatus contains a
photoreceptor drum 1 having around the same in the rotation
direction a charging device 2, an image writing unit 3 , such as
laser light, a developing device 4, a primary transferring unit 5
and a cleaning unit 6, and toners of respective colors, i.e.,
black, yellow, magenta and cyan, are installed in developing units
4.sub.1 to 4.sub.4 of the developing device 4, respectively. An
intermediate transfer belt 7, which is in contact with the surface
of the photoreceptor drum 1 and runs between the photoreceptor drum
1 and the primary transferring unit 5 in the direction shown by the
arrow, is hung by tension rolls 8a, 8b and 8c and a backup roll 9.
A bias roll 10 and a belt cleaner 11 are arranged to face the
backup roll 9 and the tension roll 8a, respectively.
[0141] A part where the primary transferring unit 5 pushes the
photoreceptor drum 1 through the intermediate transfer belt 7 is a
primary transferring part, and a part where the bias roll 10 pushes
the backup roll 9 is a secondary transferring part. A toner image
is transferred from the intermediate transfer belt 7 to transfer
paper P supplied from a paper supplying tray 13 to the secondary
transferring part, and then the transfer paper P is transported to
and fixed by a fixing unit 14 containing a pressure roll 15 having
a heater inside and a transfer belt 16. A pressure pad 17 for
pushing the transfer belt 16 onto the pressure roll 15 and a belt
guide 18 are arranged inside the transfer belt 16.
[0142] The invention will be described in more detail with
reference to the following examples, but the invention is not
construed as being limited thereto.
[0143] All the "parts" referred below are parts by weight. The
average particle diameter of the toner is measured by a Coulter
Counter (Type TA2, produced by Beckman Coulter, Inc.). The particle
size distribution of the toner, which is represented by GSDv, is a
square root of d.sub.50/d.sub.16, which is obtained by dividing the
particle diameter d.sub.50, at which the accumulated volume
diameter from the small diameter side becomes 50%, by the particle
diameter d.sub.16, at which the accumulated volume diameter from
the small diameter side becomes 16%. The melting point of the resin
constituting the toner particles is measured by using a
differential scanning calorimeter (DSC-50, produced by Shimadzu
Corp.) under the condition of a temperature increasing rate of
3.degree. C. per minute.
[0144] The tangent loss (tan .delta.) is measured by using a
viscoelasticity measuring apparatus (ARES, produced by Rheometric
Scientific FE, Inc.) in the following manner. The toner for
developing an electrostatic latent image is molded into a tablet
and set between parallel plates having a distance of 8 mm, and
after setting the normal force at 0, vibration of a frequency of 1
rad/sec is applied thereto. The measurement temperature is started
at 40.degree. C. and is continued until 200.degree. C. The
measurement is conducted with a measurement interval of 120 seconds
and a temperature increasing rate after starting the measurement of
1.degree. C. per minute. The distortion amount is maintained at a
suitable value for each measuring temperature during the
measurement, so as to appropriately adjust to obtain adequate
measurement values. The storage elastic modulus GL and the loss
elastic modulus GN are measured in such a manner that GL and GN
with respect to the temperature is monitored every two minutes by
using the viscoelasticity measuring apparatus (ARES, produced by
Rheometric Scientific FE, Inc.).
1 Preparation of Resin Particle Dispersion (1) Sebacic acid 789.0
parts Ethylene glycol 310.5 parts Sodium isophthalate-5-sulfonate
199.7 parts Fumaric acid 40.7 parts Dibutyl tin 2.0 parts (all
produced by Wako Pure Chemical Industries, Ltd.)
[0145] The foregoing components are mixed in a flask and heated to
240.degree. C. under reduced pressure to conduct dehydration
condensation for 6 hours, so as to obtain a resin. After cooling,
150 parts of the resin are put in 850 parts of distilled water and
mixed by agitation with a homogenizer (Ultra-Turrax, produced by
IKA Japan Co., Ltd.) under heating to 85.degree. C., followed by
cooling to room temperature to obtain a resin particle dispersion
(1). The resulting resin particles have a melting point of
71.degree. C.
2 Preparation of Resin Particle Dispersion (2) Succinic acid 769.8
parts Butanediol 450.5 parts Sodium isophthalate-5-sulfonate 199.7
parts Fumaric acid 40.7 parts Dibutyl tin 2.5 parts (all produced
by Wako Pure Chemical Industries, Ltd.)
[0146] The foregoing components are subjected to dehydration
condensation and mixed by agitation under the same conditions as in
the preparation of the resin particle dispersion (1), so as to
obtain a resin particle dispersion (2). The resulting resin
particles have a melting point of 90.degree. C.
3 Preparation of Resin Particle Dispersion (3) Azelaic acid 734.0
parts Butanediol 450.5 parts Sodium isophthalate-5-sulfonate 199.7
parts Fumaric acid 40.7 parts Dibutyl tin 2.0 parts (all produced
by Wako Pure Chemical Industries, Ltd.)
[0147] The foregoing components are subjected to dehydration
condensation and mixed by agitation under the same conditions as in
the preparation of the resin particle dispersion (1), so as to
obtain a resin particle dispersion (3). The resulting resin
particles have a melting point of 49.degree. C.
4 Preparation of Resin Particle Dispersion (4) Terephthalic acid
647.8 parts Decanediol 871.5 parts Sodium isophthalate-5-sulfonate
199.7 parts Fumaric acid 40.7 parts Dibutyl tin 2.0 parts (all
produced by Wako Pure Chemical Industries, Ltd.)
[0148] The foregoing components are subjected to dehydration
condensation and mixed by agitation under the same conditions as in
the preparation of the resin particle dispersion (1), so as to
obtain a resin particle dispersion (4). The resulting resin
particles have a melting point of 86.degree. C.
5 Preparation of Resin Particle Dispersion (5) Sebacic acid 734.0
parts Ethylene glycol 450.5 parts Sodium isophthalate-5-sulfonate
199.7 parts Fumaric acid 40.7 parts Dibutyl tin 2.0 parts (all
produced by Wako Pure Chemical Industries, Ltd.)
[0149] The foregoing components are subjected to dehydration
condensation and mixed by agitation under the same conditions as in
the preparation of the resin particle dispersion (1), so as to
obtain a resin particle dispersion (5). The resulting resin
particles have a melting point of 70.degree. C.
6 Preparation of Resin Particle Dispersion (6) Styrene 200 parts
Stearyl acrylate 800 parts Sodium P-styrene sulfonate 50 parts
Dodecylmercaptan 30 parts (all produced by Wako Pure Chemical
Industries, Ltd.) Decanediol diacrylate 4 parts (produced by
Shin-Nakamura Chemical Co., Ltd.)
[0150] A solution obtained by mixing and dissolving the foregoing
components is dispersed and emulsified in a solution obtained by
dissolving 20 parts of an anionic surfactant (Newlex Paste H,
produced by NOF Corp.) in 1,300 parts of ion exchanged water in a
flask. The dispersion is slowly mixed over 10 minutes, and 200
parts of ion exchanged water having 20 parts of ammonium persulfate
(produced by Wako Pure Chemical Industries, Ltd.) dissolved therein
is put therein. After conducting substitution with nitrogen, the
content of the flask is heated over an oil bath until the content
reaches 70.degree. C. under stirring, and emulsion polymerization
is continued under the same conditions for 6 hours. Thereafter, the
reaction mixture is cooled to room temperature to obtain a resin
particle dispersion (6). The resulting resin particles have a
melting point of 66.degree. C.
7 Preparation of Colorant Dispersion (1) Phthalocyanine pigment 250
parts (PV Fast Blue, produced by Dainichiseika Colour &
Chemicals Mfg. Co., Ltd.) Anionic surfactant 20 parts (Neogen RK,
produced by Dai-ichi Kogyo Seiyaku Co., Ltd.) Ion exchanged water
730 parts
[0151] The foregoing components are mixed and dissolved, and the
mixture is dispersed by using a homogenizer (Ultra-Turrax, produced
by IKA Corp.), so as to obtain a colorant dispersion (1) having a
colorant (phthalocyanine pigment) dispersed therein.
8 Preparation of Colorant Dispersion (2) Yellow pigment 200 parts
(C.I.PY180, produced by Clariant Japan Co., Ltd.) Anionic
surfactant 20 parts (Newlex R, produced by NOF Corp.) Ion exchanged
water 780 parts
[0152] The foregoing components are mixed and dissolved, and the
mixture is dispersed by using a homogenizer (Ultra-Turrax, produced
by IKA Corp.), so as to obtain a colorant dispersion (2) having a
colorant (yellow pigment) dispersed therein.
9 Preparation of Colorant Dispersion (3) Magenta pigment 300 parts
(C.I.PR122, produced by Dainichiseika Colour & Chemicals Mfg.
Co., Ltd.) Anionic surfactant 25 parts (Newlex R, produced by NOF
Corp.) Ion exchanged water 675 parts
[0153] The foregoing components are mixed and dissolved, and the
mixture is dispersed by using a homogenizer (Ultra-Turrax, produced
by IKA Corp.), so as to obtain a colorant dispersion (3) having a
colorant (magenta pigment) dispersed therein.
10 Preparation of Colorant Dispersion (4) Carbon black 230 parts
(Regal 330, produced by Cabot Inc.) Anionic surfactant 25 parts
(Newlex R, produced by NOF Corp.) Ion exchanged water 745 parts
[0154] The foregoing components are mixed and dissolved, and the
mixture is dispersed by using a homogenizer (Ultra-Turrax, produced
by IKA Corp.), so as to obtain a colorant dispersion (4) having a
colorant (carbon black) dispersed therein.
11 Preparation of Releasing Agent Particle Dispersion Polyethylene
wax (molecular weight: 730) 400 parts (Polywax 725, produced by
Toyo Petrolite Co., Ltd.) Anionic surfactant 20 parts (Newlex R,
produced by NOF Corp.) Ion exchanged water 580 parts
[0155] The foregoing components are dissolved by mixing, and the
mixture is dispersed by using a homogenizer (Ultra-Turrax, produced
by IKA Corp.), followed by subjecting to a dispersion treatment by
a pressure discharge type homogenizer, so as to obtain a releasing
agent particle dispersion having releasing agent particle
(polyethylene wax) dispersed therein. The releasing agent particle
dispersion is dried, and the measurement of the softening point of
the remaining releasing agent reveals 98.degree. C.
12 Preparation of Ester Compound Particle Dispersion (1) Stearyl
stearate 100 parts (Rikemal SL-800, produced by Riken Vitamin Co.,
Ltd.) (Carbon number of alkyl group of ester compound: 17)
(Molecular weight: 522) Anionic surfactant 2 parts (Newlex R,
produced by NOF Corp.) Ion exchanged water 300 parts
[0156] The foregoing components are dissolved by mixing, and the
mixture is dispersed by using a homogenizer (Ultra-Turrax, produced
by IKA Corp.), followed by subjecting to a dispersion treatment by
a pressure discharge type homogenizer, so as to obtain an ester
compound particle dispersion (1) having an ester compound particle
dispersed therein.
13 Preparation of Ester Compound Particle Dispersion (2) Butyl
stearate 100 parts (NIKKO LBS, produced by Nikko Chemicals Co.,
Ltd.) (Carbon number of alkyl group of ester compound: 17)
(Molecular weight: 354) Anionic surfactant 2 parts (Newlex R,
produced by NOF Corp.) Ion exchanged water 300 parts
[0157] The foregoing components are dissolved by mixing, and the
mixture is dispersed by using a homogenizer (Ultra-Turrax, produced
by IKA Corp.), followed by subjecting to a dispersion treatment by
a pressure discharge type homogenizer, so as to obtain an ester
compound particle dispersion (2) having an ester compound particle
dispersed therein.
14 Preparation of Ester Compound Particle Dispersion (3) Butyl
laurate 100 parts (produced by NOF Corp.) (Carbon number of alkyl
group of ester compound: 11) (Molecular weight: 256) Anionic
surfactant 2 parts (Newlex R, produced by NOF Corp.) Ion exchanged
water 300 parts
[0158] The foregoing components are dissolved by mixing, and the
mixture is dispersed by using a homogenizer (Ultra-Turrax, produced
by IKA Corp.), followed by subjecting to a dispersion treatment by
a pressure discharge type homogenizer, so as to obtain an ester
compound particle dispersion (3) having an ester compound particle
dispersed therein.
15 Preparation of Ester Compound Particle Dispersion (4) Glycerin
mono/dibehenate 100 parts (Rikemal B-200, produced by Riken Vitamin
Co., Ltd.) (Carbon number of alkyl group of ester compound: 21)
(Molecular weight: 617) Anionic surfactant 2 parts (Newlex R,
produced by NOF Corp.) Ion exchanged water 300 parts
[0159] The foregoing components are dissolved by mixing, and the
mixture is dispersed by using a homogenizer (Ultra-Turrax, produced
by IKA Corp.), followed by subjecting to a dispersion treatment by
a pressure discharge type homogenizer, so as to obtain an ester
compound particle dispersion (4) having an ester compound particle
dispersed therein.
16 Preparation of Ester Compound Particle Dispersion (5) Sorbitan
monostearate 100 parts (Emalex SPE-100, produced by Nippon Nyukazai
Co., Ltd.) (Carbon number of alkyl group of ester compound: 17)
(Molecular weight: 431) Anionic surfactant 2 parts (Newlex R,
produced by NOF Corp.) Ion exchanged water 300 parts
[0160] The foregoing components are dissolved by mixing, and the
mixture is dispersed by using a homogenizer (Ultra-Turrax, produced
by IKA Corp.), followed by subjecting to a dispersion treatment by
a pressure discharge type homogenizer, so as to obtain an ester
compound particle dispersion (5) having an ester compound particle
dispersed therein.
17 Preparation of Ester Compound Particle Dispersion (6)
Cholesteryl stearate 100 parts (produced by Nikko Chemicals Co.,
Ltd.) (Carbon number of alkyl group of ester compound: 17)
(Molecular weight: 649) Anionic surfactant 2 parts (Newlex R,
produced by NOF Corp.) Ion exchanged water 300 parts
[0161] The foregoing components are dissolved by mixing, and the
mixture is dispersed by using a homogenizer (Ultra-Turrax, produced
by IKA Corp.), followed by subjecting to a dispersion treatment by
a pressure discharge type homogenizer, so as to obtain an ester
compound particle dispersion (6) having an ester compound particle
dispersed therein.
18 Preparation of Ester Compound Particle Dispersion (7) n-Amyl
n-valerate 100 parts (produced by Wako Pure Chemical Industries,
Ltd.) (Carbon number of alkyl group of ester compound: 5)
(Molecular weight: 172) Anionic surfactant 2 parts (Newlex R,
produced by NOF Corp.) Ion exchanged water 300 parts
[0162] The foregoing components are dissolved by mixing, and the
mixture is dispersed by using a homogenizer (Ultra-Turrax, produced
by IKA Corp.), followed by subjecting to a dispersion treatment by
a pressure discharge type homogenizer, so as to obtain an ester
compound particle dispersion (7) having an ester compound particle
dispersed therein.
[0163] Production Example of Developer for Developing Electrostatic
Latent Image (1)
[0164] (Aggregation Step)
19 Preparation of Aggregated Particles Resin particle dispersion
(1) 2,833 parts Colorant dispersion (1) 100 parts Releasing agent
particle dispersion 125 parts Ester compound particle dispersion
(1) 200 parts Lauroyl peroxide 10 parts Aluminum sulfate 5 parts
(produced by Wako Pure Chemical Industries, Ltd.) Ion exchanged
water 100 parts
[0165] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2.2. The contents of the flask
are dispersed by using a homogenizer (Ultra-Turrax T50, produced by
IKA Corp.) and heated over an oil bath for heating to 62.degree. C.
under stirring. After maintaining at 62.degree. C. for 60 minutes,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 4.8 .mu.m
are formed. After further maintaining at 62.degree. C. for 30
minutes, the observation by an optical microscope confirms that
aggregated particles having an average particle diameter of about
5.4 .mu.m are formed.
[0166] (Coalescing Step)
[0167] The aggregated particle dispersion has pH of 2.2. An aqueous
solution obtained by diluting sodium carbonate (produced by Wako
Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 5.5, and the mixture is then
heated to 90.degree. C. under continuous stirring, followed by
maintaining for 3 hours.
[0168] Thereafter, the reaction product is filtered and
sufficiently washed with ion exchanged water, followed by drying by
using a vacuum dryer, so as to obtain toner particles.
[0169] (Evaluation)
[0170] The resulting toner particles have an average particle
diameter of 5.2 .mu.m. 1 Part of colloidal silica (R972, produced
by Nippon Aerosil Co., Ltd.) is mixed with and externally added to
100 parts of the toner particles by using a Henschel mixer to
obtain a toner for developing an electrostatic latent image.
[0171] Preparation of Developer for Developing Electrostatic Latent
Image
[0172] 100 Parts of ferrite particles (produced by Powder Tech Co.,
Ltd., average particle diameter: 50 .mu.m) and 2.5 parts of a
methacrylate resin (produced by Mitsubishi Rayon Co., Ltd.,
molecular weight: 95,000) are placed in a pressure kneader along
with 500 parts of toluene, and mixed by stirring at ordinary
temperature for 15 minutes. Thereafter, the temperature is
increased to 70.degree. C. with mixing under reduced pressure, and
after distilling off the toluene and cooling, classification is
conducted by using a sieve of 105 .mu.m to produce a ferrite
carrier (resin coated carrier).
[0173] The ferrite carrier is mixed with the toner for developing
an electrostatic latent image to produce a two-component developer
for developing an electrostatic latent image (1) having a toner
concentration of 7% by weight.
[0174] Production Example of Developer for Developing Electrostatic
Latent Image (2)
[0175] (Aggregation Step)
20 Preparation of Aggregated Particles Resin particle dispersion
(2) 2,833 parts Colorant dispersion (1) 100 parts Releasing agent
particle dispersion 125 parts Ester compound particle dispersion
(1) 200 parts Lauroyl peroxide 10 parts Aluminum sulfate 5 parts
(produced by Wako Pure Chemical Industries, Ltd.) Ion exchanged
water 100 parts
[0176] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2.0. The contents of the flask
are dispersed by using a homogenizer (Ultra-Turrax T50, produced by
IKA Corp.) and heated over an oil bath for heating to 82.degree. C.
under stirring. After maintaining at 82.degree. C. for 90 minutes,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 5.6 .mu.m
are formed. After further maintaining at 82.degree. C. for 60
minutes, the observation by an optical microscope confirms that
aggregated particles having an average particle diameter of about
5.9 .mu.m are formed.
[0177] (Coalescing Step)
[0178] The aggregated particle dispersion has pH of 2.1. An aqueous
solution obtained by diluting sodium carbonate (produced by Wako
Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 6.0, and the mixture is then
heated to 97.degree. C. under continuous stirring, followed by
maintaining for 5 hours.
[0179] Thereafter, the reaction product is filtered and
sufficiently washed with ion exchanged water, followed by drying by
using a vacuum dryer, so as to obtain toner particles.
[0180] (Evaluation)
[0181] The resulting toner particles have an average particle
diameter of 5.7 .mu.m. A developer for developing an electrostatic
latent image (2) is prepared by using the resulting toner particles
in the same manner as in the preparation of the developer for
developing an electrostatic latent image (1).
[0182] Production Example of Developer for Developing Electrostatic
Latent Image (3)
[0183] (Aggregation Step)
21 Preparation of Aggregated Particles Resin particle dispersion
(3) 2,833 parts Colorant dispersion (1) 100 parts Releasing agent
particle dispersion 125 parts Ester compound particle dispersion
(1) 200 parts Lauroyl peroxide 12 parts Aluminum sulfate 5 parts
(produced by Wako Pure Chemical Industries, Ltd.) Ion exchanged
water 100 parts
[0184] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2.0. The contents of the flask
are dispersed by using a homogenizer (Ultra-Turrax T50, produced by
IKA Corp.) and heated over an oil bath for heating to 46.degree. C.
under stirring. After maintaining at 46.degree. C. for 60 minutes,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 4.4 .mu.m
are formed. After farther maintaining at 46.degree. C. for 60
minutes, the observation by an optical microscope confirms that
aggregated particles having an average particle diameter of about
4.5 .mu.m are formed.
[0185] (Coalescing Step)
[0186] The aggregated particle dispersion has pH of 2.2. An aqueous
solution obtained by diluting sodium carbonate (produced by Wako
Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 5.2, and the mixture is then
heated to 75.degree. C. under continuous stirring, followed by
maintaining for 4 hours.
[0187] Thereafter, the reaction product is filtered and
sufficiently washed with ion exchanged water, followed by drying by
using a vacuum dryer, so as to obtain toner particles.
[0188] (Evaluation)
[0189] The resulting toner particles have an average particle
diameter of 4.7 .mu.m. A developer for developing an electrostatic
latent image (3) is prepared by using the resulting toner particles
in the same manner as in the preparation of the developer for
developing an electrostatic latent image (1).
[0190] Production Example of Developer for Developing Electrostatic
Latent Image (4)
[0191] (Aggregation Step)
22 Preparation of Aggregated Particles Resin particle dispersion
(4) 2,833 parts Colorant dispersion (1) 100 parts Releasing agent
particle dispersion 125 parts Ester compound particle dispersion
(1) 200 parts Lauroyl peroxide 10 parts Aluminum sulfate 5 parts
(produced by Wako Pure Chemical Industries, Ltd.) Ion exchanged
water 100 parts
[0192] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2.0. The contents of the flask
are dispersed by using a homogenizer (Ultra-Turrax T50, produced by
IKA Corp.) and heated over an oil bath for heating to 86.degree. C.
under stirring. After maintaining at 86.degree. C. for 80 minutes,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 6.2 .mu.m
are formed. After further maintaining at 86.degree. C. for 90
minutes, the observation by an optical microscope confirms that
aggregated particles having an average particle diameter of about
6.5 .mu.m are formed.
[0193] (Coalescing Step)
[0194] The aggregated particle dispersion has pH of 2.2. An aqueous
solution obtained by diluting sodium carbonate (produced by Wako
Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 6.2, and the mixture is then
heated to 95.degree. C. under continuous stirring, followed by
maintaining for 5 hours.
[0195] Thereafter, the reaction product is filtered and
sufficiently washed with ion exchanged water, followed by drying by
using a vacuum dryer, so as to obtain toner particles.
[0196] (Evaluation)
[0197] The resulting toner particles have an average particle
diameter of 6.6 .mu.m. A developer for developing an electrostatic
latent image (4) is prepared by using the resulting toner particles
in the same manner as in the preparation of the developer for
developing an electrostatic latent image (1).
[0198] Production Example of Developer for Developing Electrostatic
Latent Image (5)
[0199] (Aggregation Step)
23 Preparation of Aggregated Particles Resin particle dispersion
(5) 2,833 parts Colorant dispersion (1) 100 parts Releasing agent
particle dispersion 125 parts Ester compound particle dispersion
(1) 200 parts Lauroyl peroxide 10 parts Aluminum sulfate 5 parts
(produced by Wako Pure Chemical Industries, Ltd.) Ion exchanged
water 100 parts
[0200] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2.0. The contents of the flask
are dispersed by using a homogenizer (Ultra-Turrax T50, produced by
IKA Corp.) and heated over an oil bath for heating to 65.degree. C.
under stirring. After maintaining at 65.degree. C. for 70 minutes,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 5.5 .mu.m
are formed. After further maintaining at 65.degree. C. for 60
minutes, the observation by an optical microscope confirms that
aggregated particles having an average particle diameter of about
5.7 .mu.m are formed.
[0201] (Coalescing Step)
[0202] The aggregated particle dispersion has pH of 2.3. An aqueous
solution obtained by diluting sodium carbonate (produced by Wako
Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 5.5, and the mixture is then
heated to 90.degree. C. under continuous stirring, followed by
maintaining for 5 hours.
[0203] Thereafter, the reaction product is filtered and
sufficiently washed with ion exchanged water, followed by drying by
using a vacuum dryer, so as to obtain toner particles.
[0204] (Evaluation)
[0205] The resulting toner particles have an average particle
diameter of 5.9 .mu.m. A developer for developing an electrostatic
latent image (5) is prepared by using the resulting toner particles
in the same manner as in the preparation of the developer for
developing an electrostatic latent image (1).
[0206] Production Example of Developer for Developing Electrostatic
Latent Image (6)
[0207] (Aggregation Step)
24 Preparation of Aggregated Particles Resin particle dispersion
(6) 1,063 parts Colorant dispersion (1) 100 parts Releasing agent
particle dispersion 125 parts Ester compound particle dispersion
(1) 200 parts Lauroyl peroxide 8 parts Aluminum sulfate 5 parts
(produced by Wako Pure Chemical Industries, Ltd.) Ion exchanged
water 1000 parts
[0208] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2.0. The contents of the flask
are dispersed by using a homogenizer (Ultra-Turrax T50, produced by
IKA Corp.) and heated over an oil bath for heating to 64.degree. C.
under stirring. After maintaining at 64.degree. C. for 50 minutes,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 5.1 .mu.m
are formed. After further maintaining at 64.degree. C. for 40
minutes, the observation by an optical microscope confirms that
aggregated particles having an average particle diameter of about
5.2 .mu.m are formed.
[0209] (Coalescing Step)
[0210] The aggregated particle dispersion has pH of 2.2. An aqueous
solution obtained by diluting sodium hydrogencarbonate (produced by
Wako Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 7.2, and the mixture is then
heated to 90.degree. C. under continuous stirring, followed by
maintaining for 6 hours.
[0211] Thereafter, the reaction product is filtered and
sufficiently washed with ion exchanged water, followed by drying by
using a vacuum dryer, so as to obtain toner particles.
[0212] (Evaluation)
[0213] The resulting toner particles have an average particle
diameter of 5.4 .mu.m. A developer for developing an electrostatic
latent image (6) is prepared by using the resulting toner particles
in the same manner as in the preparation of the developer for
developing an electrostatic latent image (1).
[0214] Production Example of Developer for Developing Electrostatic
Latent Image (7)
[0215] (Aggregation Step)
25 Preparation of Aggregated Particles Resin particle dispersion
(1) 2,767 parts Colorant dispersion (2) 117 parts Releasing agent
particle dispersion 125 parts Ester compound particle dispersion
(1) 200 parts Lauroyl peroxide 12 parts Aluminum sulfate 7 parts
(produced by Wako Pure Chemical Industries, Ltd.) Ion exchanged
water 150 parts
[0216] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2.0. The contents of the flask
are dispersed by using a homogenizer (Ultra-Turrax T50, produced by
IKA Corp.) and heated over an oil bath for heating to 64.degree. C.
under stirring. After maintaining at 68.degree. C. for 50 minutes,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 4.9 .mu.m
are formed. After further maintaining at 68.degree. C. for 60
minutes, the observation by an optical microscope confirms that
aggregated particles having an average particle diameter of about
5.3 .mu.m are formed.
[0217] (Coalescing Step)
[0218] The aggregated particle dispersion has pH of 2.5. An aqueous
solution obtained by diluting sodium hydrogencarbonate (produced by
Wako Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 5.2, and the mixture is then
heated to 90.degree. C. under continuous stirring, followed by
maintaining for 6 hours.
[0219] Thereafter, the reaction product is filtered and
sufficiently washed with ion exchanged water, followed by drying by
using a vacuum dryer, so as to obtain toner particles.
[0220] (Evaluation)
[0221] The resulting toner particles have an average particle
diameter of 5.5 .mu.m. A developer for developing an electrostatic
latent image (7) is prepared by using the resulting toner particles
in the same manner as in the preparation of the developer for
developing an electrostatic latent image (1).
[0222] Production Example of Developer for Developing Electrostatic
Latent Image (8)
[0223] (Aggregation Step)
26 Preparation of Aggregated Particles Resin particle dispersion
(1) 2,667 parts Colorant dispersion (3) 250 parts Releasing agent
particle dispersion 125 parts Ester compound particle dispersion
(1) 200 parts Lauroyl peroxide 7 parts Aluminum sulfate 7 parts
(produced by Wako Pure Chemical Industries, Ltd.) Ion exchanged
water 120 parts
[0224] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2.0. The contents of the flask
are dispersed by using a homogenizer (Ultra-Turrax T50, produced by
IKA Corp.) and heated over an oil bath for heating to 68.degree. C.
under stirring. After maintaining at 68.degree. C. for 60 minutes,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 4.5 .mu.m
are formed. After further maintaining at 68.degree. C. for 60
minutes, the observation by an optical microscope confirms that
aggregated particles having an average particle diameter of about
5.0 .mu.m are formed.
[0225] (Coalescing Step)
[0226] The aggregated particle dispersion has pH of 2.4. An aqueous
solution obtained by diluting sodium hydrogencarbonate (produced by
Wako Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 7.2, and the mixture is then
heated to 90.degree. C. under continuous stirring, followed by
maintaining for 4 hours.
[0227] Thereafter, the reaction product is filtered and
sufficiently washed with ion exchanged water, followed by drying by
using a vacuum dryer, so as to obtain toner particles.
[0228] (Evaluation)
[0229] The resulting toner particles have an average particle
diameter of 5.2 .mu.m. A developer for developing an electrostatic
latent image (8) is prepared by using the resulting toner particles
in the same manner as in the preparation of the developer for
developing an electrostatic latent image (1).
[0230] Production Example of Developer for Developing Electrostatic
Latent Image (9)
[0231] (Aggregation Step)
27 Preparation of Aggregated Particles Resin particle dispersion
(1) 2,833 parts Colorant dispersion (4) 109 parts Releasing agent
particle dispersion 125 parts Ester compound particle dispersion
(1) 200 parts Lauroyl peroxide 10 parts Aluminum sulfate 5 parts
(produced by Wako Pure Chemical Industries, Ltd.) Ion exchanged
water 100 parts
[0232] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2.0. The contents of the flask
are dispersed by using a homogenizer (Ultra-Turrax T50, produced by
IKA Corp.) and heated over an oil bath for heating to 67.degree. C.
under stirring. After maintaining at 67.degree. C. for 60 minutes,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 4.8 .mu.m
are formed. After further maintaining at 67.degree. C. for 60
minutes, the observation by an optical microscope confirms that
aggregated particles having an average particle diameter of about
5.0 .mu.m are formed.
[0233] (Coalescing Step)
[0234] The aggregated particle dispersion has pH of 2.3. An aqueous
solution obtained by diluting sodium hydrogencarbonate (produced by
Wako Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 5.5, and the mixture is then
heated to 90.degree. C. under continuous stirring, followed by
maintaining for 4 hours.
[0235] Thereafter, the reaction product is filtered and
sufficiently washed with ion exchanged water, followed by drying by
using a vacuum dryer, so as to obtain toner particles.
[0236] (Evaluation)
[0237] The resulting toner particles have an average particle
diameter of 5.2 .mu.m. A developer for developing an electrostatic
latent image (9) is prepared by using the resulting toner particles
in the same manner as in the preparation of the developer for
developing an electrostatic latent image (1).
[0238] Production Example of Developer for Developing Electrostatic
Latent Image (10)
[0239] (Aggregation Step)
28 Preparation of Aggregated Particles Resin particle dispersion
(1) 2,833 parts Colorant dispersion (1) 100 parts Releasing agent
particle dispersion 125 parts Ester compound particle dispersion
(2) 200 parts Lauroyl peroxide 10 parts Aluminum sulfate 5 parts
(produced by Wako Pure Chemical Industries, Ltd.) Ion exchanged
water 100 parts
[0240] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2.0. The contents of the flask
are dispersed by using a homogenizer (Ultra-Turrax T50, produced by
IKA Corp.) and heated over an oil bath for heating to 65.degree. C.
under stirring. After maintaining at 65.degree. C. for 60 minutes,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 4.9 .mu.m
are formed. After further maintaining at 65.degree. C. for 60
minutes, the observation by an optical microscope confirms that
aggregated particles having an average particle diameter of about
5.1 .mu.m are formed.
[0241] (Coalescing Step)
[0242] The aggregated particle dispersion has pH of 2.2. An aqueous
solution obtained by diluting sodium carbonate (produced by Wako
Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 5.0, and the mixture is then
heated to 90.degree. C. under continuous stirring, followed by
maintaining for 4 hours.
[0243] Thereafter, the reaction product is filtered and
sufficiently washed with ion exchanged water, followed by drying by
using a vacuum dryer, so as to obtain toner particles.
[0244] (Evaluation)
[0245] The resulting toner particles have an average particle
diameter of 5.2 .mu.m. A developer for developing an electrostatic
latent image (10) is prepared by using the resulting toner
particles in the same manner as in the preparation of the developer
for developing an electrostatic latent image (1).
[0246] Production Example of Developer for Developing Electrostatic
Latent Image (11)
[0247] (Aggregation Step)
29 Preparation of Aggregated Particles Resin particle dispersion
(1) 2,833 parts Colorant dispersion (1) 100 parts Releasing agent
particle dispersion 125 parts Ester compound particle dispersion
(3) 200 parts Lauroyl peroxide 10 parts Aluminum sulfate 5 parts
(produced by Wako Pure Chemical Industries, Ltd.) Ion exchanged
water 100 parts
[0248] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2.0. The contents of the flask
are dispersed by using a homogenizer (Ultra-Turrax T50, produced by
IKA Corp.) and heated over an oil bath for heating to 65.degree. C.
under stirring. After maintaining at 65.degree. C. for 60 minutes,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 4.5 .mu.m
are formed. After further maintaining at 65.degree. C. for 60
minutes, the observation by an optical microscope confirms that
aggregated particles having an average particle diameter of about
4.8 .mu.m are formed.
[0249] (Coalescing Step)
[0250] The aggregated particle dispersion has pH of 2.2. An aqueous
solution obtained by diluting sodium carbonate (produced by Wako
Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 5.0, and the mixture is then
heated to 90.degree. C. under continuous stirring, followed by
maintaining for 4 hours.
[0251] Thereafter, the reaction product is filtered and
sufficiently washed with ion exchanged water, followed by drying by
using a vacuum dryer, so as to obtain toner particles.
[0252] (Evaluation)
[0253] The resulting toner particles have an average particle
diameter of 5.0 .mu.m. A developer for developing an electrostatic
latent image (11) is prepared by using the resulting toner
particles in the same manner as in the preparation of the developer
for developing an electrostatic latent image (1).
[0254] Production Example of Developer for Developing Electrostatic
Latent Image (12)
[0255] (Aggregation Step)
30 Preparation of Aggregated Particles Resin particle dispersion
(1) 2,833 parts Colorant dispersion (1) 100 parts Releasing agent
particle dispersion 125 parts Ester compound particle dispersion
(4) 200 parts Lauroyl peroxide 10 parts Aluminum sulfate 5 parts
(produced by Wako Pure Chemical Industries, Ltd.) Ion exchanged
water 100 parts
[0256] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2.0. The contents of the flask
are dispersed by using a homogenizer (Ultra-Turrax T50, produced by
IKA Corp.) and heated over an oil bath for heating to 65.degree. C.
under stirring. After maintaining at 65.degree. C. for 60 minutes,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 4.9 .mu.m
are formed. After further maintaining at 65.degree. C. for 60
minutes, the observation by an optical microscope confirms that
aggregated particles having an average particle diameter of about
4.9 .mu.m are formed.
[0257] (Coalescing Step)
[0258] The aggregated particle dispersion has pH of 2.2. An aqueous
solution obtained by diluting sodium carbonate (produced by Wako
Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 5.1, and the mixture is then
heated to 90.degree. C. under continuous stirring, followed by
maintaining for 4 hours.
[0259] Thereafter, the reaction product is filtered and
sufficiently washed with ion exchanged water, followed by drying by
using a vacuum dryer, so as to obtain toner particles.
[0260] (Evaluation)
[0261] The resulting toner particles have an average particle
diameter of 5.1 .mu.m. A developer for developing an electrostatic
latent image (12) is prepared by using the resulting toner
particles in the same manner as in the preparation of the developer
for developing an electrostatic latent image (1).
[0262] Production Example of Developer for Developing Electrostatic
Latent Image (13)
[0263] (Aggregation Step)
31 Preparation of Aggregated Particles Resin particle dispersion
(1) 2,833 parts Colorant dispersion (1) 100 parts Releasing agent
particle dispersion 125 parts Ester compound particle dispersion
(5) 200 parts Lauroyl peroxide 10 parts Aluminum sulfate 5 parts
(produced by Wako Pure Chemical Industries, Ltd.) Ion exchanged
water 100 parts
[0264] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2.0. The contents of the flask
are dispersed by using a homogenizer (Ultra-Turrax T50, produced by
IKA Corp.) and heated over an oil bath for heating to 65.degree. C.
under stirring. After maintaining at 65.degree. C. for 60 minutes,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 4.9 .mu.m
are formed. After further maintaining at 65.degree. C. for 60
minutes, the observation by an optical microscope confirms that
aggregated particles having an average particle diameter of about
5.4 .mu.m are formed.
[0265] (Coalescing Step)
[0266] The aggregated particle dispersion has pH of 2.2. An aqueous
solution obtained by diluting sodium carbonate (produced by Wako
Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 4.8, and the mixture is then
heated to 90.degree. C. under continuous stirring, followed by
maintaining for 4 hours.
[0267] Thereafter, the reaction product is filtered and
sufficiently washed with ion exchanged water, followed by drying by
using a vacuum dryer, so as to obtain toner particles.
[0268] (Evaluation)
[0269] The resulting toner particles have an average particle
diameter of 5.7 .mu.m. A developer for developing an electrostatic
latent image (13) is prepared by using the resulting toner
particles in the same manner as in the preparation of the developer
for developing an electrostatic latent image (1).
[0270] Production Example of Developer for Developing Electrostatic
Latent Image (14)
[0271] (Aggregation Step)
32 Preparation of Aggregated Particles Resin particle dispersion
(1) 2,833 parts Colorant dispersion (1) 100 parts Releasing agent
particle dispersion 125 parts Ester compound particle dispersion
(6) 200 parts Lauroyl peroxide 10 parts Aluminum sulfate 5 parts
(produced by Wako Pure Chemical Industries, Ltd.) Ion exchanged
water 100 parts
[0272] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2.0. The contents of the flask
are dispersed by using a homogenizer (Ultra-Turrax T50, produced by
IKA Corp.) and heated over an oil bath for heating to 65.degree. C.
under stirring. After maintaining at 65.degree. C. for 60 minutes,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 5.0 .mu.m
are formed. After further maintaining at 65.degree. C. for 60
minutes, the observation by an optical microscope confirms that
aggregated particles having an average particle diameter of about
5.2 .mu.m are formed.
[0273] (Coalescing Step)
[0274] The aggregated particle dispersion has pH of 2.2. An aqueous
solution obtained by diluting sodium carbonate (produced by Wako
Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 5.2, and the mixture is then
heated to 90.degree. C. under continuous stirring, followed by
maintaining for 4 hours.
[0275] Thereafter, the reaction product is filtered and
sufficiently washed with ion exchanged water, followed by drying by
using a vacuum dryer, so as to obtain toner particles.
[0276] (Evaluation)
[0277] The resulting toner particles have an average particle
diameter of 5.3 .mu.m. A developer for developing an electrostatic
latent image (14) is prepared by using the resulting toner
particles in the same manner as in the preparation of the developer
for developing an electrostatic latent image (1).
[0278] Production Example of Developer for Developing Electrostatic
Latent Image (15)
[0279] (Aggregation Step)
33 Preparation of Aggregated Particles Resin particle dispersion
(1) 2,833 parts Colorant dispersion (1) 100 parts Releasing agent
particle dispersion 125 parts Ester compound particle dispersion
(1) 100 parts Ester compound particle dispersion (6) 100 parts
Lauroyl peroxide 10 parts Aluminum sulfate 5 parts (produced by
Wako Pure Chemical Industries, Ltd.) Ion exchanged water 100
parts
[0280] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2.0. The contents of the flask
are dispersed by using a homogenizer (Ultra-Turrax T50, produced by
IKA Corp.) and heated over an oil bath for heating to 65.degree. C.
under stirring. After maintaining at 65.degree. C. for 60 minutes,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 4.8 .mu.m
are formed. After further maintaining at 65.degree. C. for 60
minutes, the observation by an optical microscope confirms that
aggregated particles having an average particle diameter of about
5.1 .mu.m are formed.
[0281] (Coalescing Step)
[0282] The aggregated particle dispersion has pH of 2.2. An aqueous
solution obtained by diluting sodium carbonate (produced by Wako
Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 5.0, and the mixture is then
heated to 90.degree. C. under continuous stirring, followed by
maintaining for 4 hours.
[0283] Thereafter, the reaction product is filtered and
sufficiently washed with ion exchanged water, followed by drying by
using a vacuum dryer, so as to obtain toner particles.
[0284] (Evaluation)
[0285] The resulting toner particles have an average particle
diameter of 5.5 .mu.m. A developer for developing an electrostatic
latent image (15) is prepared by using the resulting toner
particles in the same manner as in the preparation of the developer
for developing an electrostatic latent image (1).
[0286] Production Example of Developer for Developing Electrostatic
Latent Image (16)
[0287] (Aggregation Step)
34 Preparation of Aggregated Particles Resin particle dispersion
(1) 2,833 parts Colorant dispersion (1) 100 parts Releasing agent
particle dispersion 125 parts Lauroyl peroxide 10 parts Aluminum
sulfate 5 parts (produced by Wako Pure Chemical Industries, Ltd.)
Ion exchanged water 300 parts
[0288] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2.0. The contents of the flask
are dispersed by using a homogenizer (Ultra-Turrax T50, produced by
IKA Corp.) and heated over an oil bath for heating to 65.degree. C.
under stirring. After maintaining at 65.degree. C. for 60 minutes,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 4.9 .mu.m
are formed. After further maintaining at 65.degree. C. for 60
minutes, the observation by an optical microscope confirms that
aggregated particles having an average particle diameter of about
5.3 .mu.m are formed.
[0289] (Coalescing Step)
[0290] The aggregated particle dispersion has pH of 2.2. An aqueous
solution obtained by diluting sodium carbonate (produced by Wako
Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 5.0, and the mixture is then
heated to 90.degree. C. under continuous stirring, followed by
maintaining for 4 hours.
[0291] Thereafter, the reaction product is filtered and
sufficiently washed with ion exchanged water, followed by drying by
using a vacuum dryer, so as to obtain toner particles.
[0292] (Evaluation)
[0293] The resulting toner particles have an average particle
diameter of 5.5 .mu.m, and the particle size distribution is
slightly broad. A developer for developing an electrostatic latent
image (16) is prepared by using the resulting toner particles in
the same manner as in the preparation of the developer for
developing an electrostatic latent image (1).
[0294] Production Example of Developer for Developing Electrostatic
Latent Image (17)
[0295] (Aggregation Step)
35 Preparation of Aggregated Particles Resin particle dispersion
(1) 2,833 parts Colorant dispersion (1) 100 parts Releasing agent
particle dispersion 125 parts Ester compound particle dispersion
(7) 100 parts Lauroyl peroxide 10 parts Aluminum sulfate 5 parts
(produced by Wako Pure Chemical Industries, Ltd.) Ion exchanged
water 300 parts
[0296] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2.0. The contents of the flask
are dispersed by using a homogenizer (Ultra-Turrax T50, produced by
IKA Corp.) and heated over an oil bath for heating to 65.degree. C.
under stirring. After maintaining at 65.degree. C. for 60 minutes,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 4.8 .mu.m
are formed. After further maintaining at 65.degree. C. for 60
minutes, the observation by an optical microscope confirms that
aggregated particles having an average particle diameter of about
5.1 .mu.m are formed.
[0297] (Coalescing Step)
[0298] The aggregated particle dispersion has pH of 2.2. An aqueous
solution obtained by diluting sodium carbonate (produced by Wako
Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 5.0, and the mixture is then
heated to 90.degree. C. under continuous stirring, followed by
maintaining for 4 hours.
[0299] Thereafter, the reaction product is filtered and
sufficiently washed with ion exchanged water, followed by drying by
using a vacuum dryer, so as to obtain toner particles.
[0300] (Evaluation)
[0301] The resulting toner particles have an average particle
diameter of 5.3 .mu.m, and the particle size distribution is
slightly broad. A developer for developing an electrostatic latent
image (17) is prepared by using the resulting toner particles in
the same manner as in the preparation of the developer for
developing an electrostatic latent image (1).
[0302] Preparation of Apparatus for Forming Image (1)
[0303] The fixing unit of a color duplicator, Acolor 930, produced
by Fuji Xerox Co., Ltd., is detached, from which the releasing oil
supplying unit is then detached, and a fixing unit containing a
fixing roll and a pressure roll having films of a
ethylene-vinylidene fluoride-tetrafluoroethylene copolymer on the
surfaces thereof is installed, so as to prepare an apparatus for
forming an image (1).
[0304] Preparation of Apparatus for Forming Image (2)
[0305] An apparatus for forming an image (2) is prepared in the
same manner as in the apparatus for forming an image (1) except
that a fixing belt formed with a polyimide film is used instead of
the pressure roll.
EXAMPLE 1
[0306] The developer of the production example of a developer for
developing an electrostatic latent image (1) is installed in a
developing unit of the apparatus for forming an image (1), and a
non-fixed image is prepared to have a solid part and a thin line
part. The non-fixed image is fixed by the fixing unit of the
apparatus for forming an image (1) in such a manner that the
rotation speed of the roll is adjusted to make the contact time of
the fixing roll and the non-fixed image be 0.04 second, with the
surface temperature of the fixing roll varying from 60 to
200.degree. C. at an interval of 5.degree. C. The fixed image is
folded inside at the substantial center of the solid part of the
fixed image to evaluate the breakage of the fixed image, and the
fixing temperature where no problem occurs is designated as the
lowest fixing temperature. Reproducibility of the thin lines,
background fogging and hot offset are evaluated with the naked
eye.
EXAMPLES 2 TO 15
[0307] Fixing is conducted and evaluated in the same manner as in
Example 1 except that the developers of the production examples of
a developer for developing an electrostatic latent image (2) to
(15) are used.
EXAMPLE 16
[0308] The developer of the production example of a developer for
developing an electrostatic latent image (1) is installed in a
developing unit of the apparatus for forming an image (2), and a
non-fixed image is prepared to have a solid part and a thin line
part. The non-fixed image is fixed under the same conditions as in
Example 1 except that the speed of the belt is adjusted to make the
contact time of the fixing belt of the fixing unit of the apparatus
for forming an image (2) and the non-fixed image be 0.08 second. A
fixing operation is conducted in the same manner as in Example 1
about other conditions and evaluation is conducted for the
image.
Comparative Example 1
[0309] A fixing operation is conducted in the same manner as in
Example 1 except that the developer of the production example of a
developer for developing an electrostatic latent image (16) is
used, and evaluation is conducted in the same manner as in Example
1.
Comparative Example 2
[0310] A fixing operation is conducted in the same manner as in
Example 1 except that the developer for Acolor 936, produced by
Fuji Xerox Co., Ltd. is used, and evaluation is conducted in the
same manner as in Example 1.
Comparative Example 3
[0311] A fixing operation is conducted in the same manner as in
Example 1 except that the developer of the production example of a
developer for developing an electrostatic latent image (17) is
used, and evaluation is conducted in the same manner as in Example
1.
[0312] Evaluation
[0313] The characteristics of the toners used in Examples 1 to 15
and Comparative Examples 1 to 3 are shown in Table 1 below, and the
average particle diameter, the particle size distribution GSDv and
the fixing characteristics thereof are shown in Table 2 below. In
the tables, Tm represents the melting point of the toner, GL(30)
represents the storage elastic modulus at 30.degree. C.; GL(Tm) and
GL(Tm+10) represent the storage elastic modulus at the melting
point and that at a temperature higher by 10.degree. C. than the
melting point, respectively; GN(Tm) and GN(Tm+10) represent the
loss elastic modulus at the melting point and that at a temperature
higher by 10.degree. C. than the melting point, respectively;
.DELTA.log GL represents .vertline.log GL(Tm+20)-log
GL(Tm+50).vertline.; and .DELTA.log GN represents .vertline.log
GN(Tm+20)-log GN(Tm+50).vertline..
36 TABLE 1 Tm GL(30) .times. GL(Tm) .times. GL(Tm + 10) .times.
GN(Tm) .times. GN(Tm + 10) .times. (.degree. C.) 10.sup.5 10.sup.5
10.sup.3 10.sup.5 10.sup.3 .DELTA.log GL .DELTA.log GN Example 1 72
2.1 7.6 5.0 7.4 4.6 1.1 1.2 Example 2 92 5.3 6.5 6.2 6.3 5.9 1.2
1.0 Example 3 49 1.6 1.8 9.2 1.9 9.0 1.4 1.4 Example 4 88 4.8 5.4
2.2 5.1 2.3 0.4 0.3 Example 5 70 2.0 8.6 1.5 8.5 1.4 0.6 0.6
Example 6 67 1.8 3.2 8.3 3.2 8.2 0.3 0.2 Example 7 71 2.1 7.7 5.2
7.4 4.5 1.0 1.2 Example 8 72 2.1 7.6 4.8 7.2 4.5 1.0 1.1 Example 9
71 2.1 7.6 5.0 7.5 4.7 0.9 0.9 Example 10 70 2.1 7.4 4.9 7.4 5.0
1.0 1.1 Example 11 72 2.1 7.3 4.6 7.2 4.4 0.6 0.5 Example 12 72 2.1
7.0 3.8 6.8 3.6 0.8 0.7 Example 13 71 2.1 7.1 5.2 6.8 5.0 1.2 1.3
Example 14 72 2.1 7.4 5.0 7.3 5.0 1.0 0.8 Example 15 72 2.1 7.1 4.0
6.8 3.6 0.7 0.6 Comparative 73 2.1 7.2 4.8 7.1 4.5 1.2 1.1 Example
1 Comparative -- 1.6 -- -- -- -- -- -- Example 2
[0314]
37 TABLE 2 Average Fixing diameter temperature Reproducibility of
Background (.mu.m) GSDv (.degree. C.) thin lines fogging Hot offset
Example 1 5.2 1.23 85 good none no occurrence Example 2 5.7 1.21
100 good none no occurrence Example 3 4.7 1.25 60 good none no
occurrence Example 4 6.6 1.26 95 good none no occurrence Example 5
5.9 1.24 80 good none no occurrence Example 6 5.4 1.22 75 good none
no occurrence Example 7 5.5 1.21 85 good none no occurrence Example
8 5.2 1.25 80 good none no occurrence Example 9 5.2 1.25 85 good
none no occurrence Example 10 5.2 1.24 85 good none no occurrence
Example 11 5.0 1.27 85 good none no occurrence Example 12 5.1 1.22
85 good none no occurrence Example 13 5.7 1.24 85 good none no
occurrence Example 14 5.3 1.23 85 good none no occurrence Example
15 5.5 1.22 85 good none no occurrence Example 16 5.2 1.22 90 good
none no occurrence Comparative 5.5 1.35 85 slightly poor slight
occurrence no occurrence Example 1 Comparative 7.0 1.34 150
slightly poor slight occurrence occurrence at Example 2 180.degree.
C. Comparative 5.3 1.39 85 slightly poor slight occurrence no
occurrence Example 3
[0315] It is understood from Tables 1 and 2 that, in comparison to
the developers for developing an electrostatic latent image
containing the toners for developing an electrostatic latent image
of Comparative Examples 1 to 3, the developers for developing an
electrostatic latent image containing the toners for developing an
electrostatic latent image of Examples 1 to 15 have a narrow
particle size distribution, i.e., the particle diameters of the
respective particles of the toner can be uniformized, and therefore
the toners for developing an electrostatic latent image can be
obtained that are excellent in reproducibility of thin lines and
cause no background fogging. Furthermore, when the same developer
for developing an electrostatic latent image containing the toner
for developing an electrostatic latent image as in Example 1 is
installed in the apparatus for forming an image (2) having a fixing
belt, and the image quality is evaluated, an image that is
excellent in reproducibility of thin lines and causes no background
fogging can be stably formed as similar to the other Examples.
[0316] Experimental examples of a toner for developing an
electrostatic latent image containing at least one resin having a
contact angle with water that is smaller than the crystalline resin
will be described below.
[0317] The contact angle with water of the resin is measured by
using a commercially available contact angle meter (Type CA-DTA,
produced by Kyowa Interface Science Co., Ltd.) in the following
manner. Powder of the resin to be measured is middle under pressure
of about 20 ton/cm2 for 30 seconds to produce a resin plate. A
water droplet is made in contact with the surface of the resin
plate, and the contact angle is measured at room temperature.
38 Preparation of Resin Particle Dispersion (7) Sebacic acid 940.7
parts Ethylene glycol 310.5 parts Fumaric acid 40.6 parts Dibutyl
tin 2.0 parts (all produced by Wako Pure Chemical Industries,
Ltd.)
[0318] The foregoing components are mixed in a flask and heated to
240.degree. C. under reduced pressure to conduct dehydration
condensation for 6 hours, so as to obtain a resin. After cooling,
it is found that the resin has a melting point of 72.degree. C. and
a contact angle with water of 88.degree.. 150 parts of the resin
are put in 850 parts of distilled water and mixed by agitation with
a homogenizer (Ultra-Turrax, produced by IKA Japan Co., Ltd.) under
heating to 85.degree. C., so as to obtain a resin particle
dispersion (7).
39 Preparation of Resin Particle Dispersion (8) Succinic acid 679.4
parts Butanediol 450.5 parts Fumaric acid 40.6 parts Dibutyl tin
2.5 parts (all produced by Wako Pure Chemical Industries, Ltd.)
[0319] The foregoing components are subjected to dehydration
condensation under the same conditions as in the resin particle
dispersion (7) to obtain a resin having a melting point of
91.degree. C. and a contact angle with water of 86.degree.. The
resin is then subjected to mixing by agitation under the same
conditions as in the resin particle dispersion (7) to obtain a
resin particle dispersion (8).
40 Preparation of Resin Particle Dispersion (9) Azelaic acid 875.1
parts Butanediol 450.5 parts Fumaric acid 40.7 parts Dibutyl tin
2.0 parts (all produced by Wako Pure Chemical Industries, Ltd.)
[0320] The foregoing components are subjected to dehydration
condensation under the same conditions as in the resin particle
dispersion (7) to obtain a resin having a melting point of
60.degree. C. and a contact angle with water of 89.degree.. The
resin is then subjected to mixing by agitation under the same
conditions as in the resin particle dispersion (7) to obtain a
resin particle dispersion (9).
41 Preparation of Resin Particle Dispersion (10) Terephthalic acid
772.4 parts Decanediol 871.5 parts Fumaric acid 40.6 parts Dibutyl
tin 2.0 parts (all produced by Wako Pure Chemical Industries,
Ltd.)
[0321] The foregoing components are subjected to dehydration
condensation under the same conditions as in the resin particle
dispersion (7) to obtain a resin having a melting point of
86.degree. C. and a contact angle with water of 82.degree.. The
resin is then subjected to mixing by agitation under the same
conditions as in the resin particle dispersion (7) to obtain a
resin particle dispersion (10).
42 Preparation of Resin Particle Dispersion (11) Sebacic acid 900.2
parts Ethylene glycol 450.5 parts Sodium isophthalate-5-sulfonate
53.2 parts Fumaric acid 40.6 parts Dibutyl tin 2.0 parts (all
produced by Wako Pure Chemical Industries, Ltd.)
[0322] The foregoing components are subjected to dehydration
condensation under the same conditions as in the resin particle
dispersion (7) to obtain a resin having a melting point of
69.degree. C. and a contact angle with water of 89.degree.. The
resin is then subjected to mixing by agitation under the same
conditions as in the resin particle dispersion (7) to obtain a
resin particle dispersion (11).
43 Preparation of Resin Particle Dispersion (12) Styrene 300 parts
Stearyl acrylate 700 parts Dodecylmercaptan 6 parts (all produced
by Wako Pure Chemical Industries, Ltd.) Decanediol diacrylate 4
parts (produced by Shin-Nakamura Chemical Co., Ltd.)
[0323] A solution obtained by mixing and dissolving the foregoing
components is dispersed and emulsified in a solution obtained by
dissolving 20 parts of an anionic surfactant (Newlex Paste H,
produced by NOF Corp.) in 1,300 parts of ion exchanged water in a
flask. The dispersion is slowly mixed over 10 minutes, and 200
parts of ion exchanged water having 20 parts of ammonium persulfate
(produced by Wako Pure Chemical Industries, Ltd.) dissolved therein
are put therein. After conducting substitution with nitrogen, the
content of the flask is heated over an oil bath until the content
reaches 70.degree. C. under stirring, and emulsion polymerization
is continued under the same conditions for 6 hours. Thereafter, the
reaction mixture is cooled to room temperature, followed by washing
and drying, so as to obtain a resin particle dispersion (12) having
a melting point of 61.degree. C. and a contact angle with water of
82.degree..
44 Preparation of Resin Particle Dispersion (13) Sebacic acid 738.4
parts Ethylene glycol 310.5 parts Sodium isophthalate-5-sulfonate
266.2 parts Fumaric acid 40.6 parts Dibutyl tin 2.0 parts (all
produced by Wako Pure Chemical Industries, Ltd.)
[0324] The foregoing components are subjected to dehydration
condensation under the same conditions as in the resin particle
dispersion (7) to obtain a resin having a melting point of
59.degree. C. and a contact angle with water of 79.degree.. The
resin is then subjected to mixing by agitation under the same
conditions as in the resin particle dispersion (7) to obtain a
resin particle dispersion (13).
45 Preparation of Resin Particle Dispersion (14) Styrene 300 parts
Stearyl acrylate 700 parts Acrylic acid 20 parts Dodecylmercaptan
12 parts (all produced by Wako Pure Chemical Industries, Ltd.)
Decanediol diacrylate 4 parts (produced by Shin-Nakamura Chemical
Co., Ltd.)
[0325] A solution obtained by mixing and dissolving the foregoing
components is dispersed and emulsified in a solution obtained by
dissolving 18 parts of an anionic surfactant (Newlex Paste H,
produced by NOF Corp.) in 1,300 parts of ion exchanged water in a
flask. The dispersion is slowly mixed over 10 minutes, and 200
parts of ion exchanged water having 16 parts of ammonium persulfate
(produced by Wako Pure Chemical Industries, Ltd.) dissolved therein
are put therein. After conducting substitution with nitrogen, the
content of the flask is heated over an oil bath until the content
reaches 70.degree. C. under stirring, and emulsion polymerization
is continued under the same conditions for 6 hours. Thereafter, the
reaction mixture is cooled to room temperature to obtain a resin
having a melting point of 56.degree. C. and a contact angle with
water of 78.degree.. A resin particle dispersion (14) is prepared
from the resultant resin under the same condition as in the resin
particle dispersion (7).
[0326] Developer for Developing Electrostatic Latent Image (18)
[0327] (Aggregation Step)
46 Preparation of Aggregated Particles Resin particle dispersion
(7) 2,400 parts (contact angle with water: 88.degree.) Resin
particle dispersion (13) 600 parts (contact angle with water:
79.degree.) Colorant particle dispersion (1) 100 parts Releasing
agent particle dispersion 63 parts Lauroyl peroxide 10 parts
Aluminum sulfate 5 parts (produced by Wako Pure Chemical
Industries, Ltd.) Ion exchanged water 100 parts
[0328] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2. The contents of the flask are
dispersed by using a homogenizer (Ultra-Turrax T50, produced by IKA
Corp.) and heated over an oil bath for heating to 68.degree. C.
under stirring. After maintaining at 68.degree. C. for 3 hours, the
observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 4.9 .mu.m
are formed. After further maintaining at 68.degree. C. for 1 hour,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 5.2 .mu.m
are formed.
[0329] (Coalescing Step)
[0330] The aggregated particle dispersion has pH of 2.4. An aqueous
solution obtained by diluting sodium carbonate (produced by Wako
Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 5.0, and the mixture is then
heated to 85.degree. C. under continuous stirring, followed by
maintaining for 3 hours. Thereafter, the reaction product is
filtered and sufficiently washed with ion exchanged water, followed
by drying by using a vacuum dryer, so as to obtain toner
particles.
[0331] The resulting toner particles have an average particle
diameter of 5.3 .mu.m. 1 Part of colloidal silica (R972, produced
by Nippon Aerosil Co., Ltd.) is externally added to 100 parts of
the toner particles, followed by mixing by a Henschel mixer, to
obtain a toner for developing an electrostatic latent image.
[0332] Preparation of Developer for Developing Electrostatic Latent
Image
[0333] 100 Parts of ferrite particles (produced by Powder Tech Co.,
Ltd., average particle diameter: 50 .mu.m) and 3.0 parts of a
methacrylate resin (produced by Mitsubishi Rayon Co., Ltd.,
molecular weight: 95,000) are placed in a pressure kneader along
with 500 parts of toluene, and mixed by stirring at ordinary
temperature for 15 minutes. Thereafter, the temperature is
increased to 70.degree. C. with mixing under reduced pressure, and
after distilling off toluene, the content is cooled and classified
by using a sieve of 105 .mu.m to produce a ferrite carrier (resin
coated carrier). The ferrite carrier is mixed with the toner for
developing an electrostatic latent image to produce a two-component
developer for developing an electrostatic latent image (18) having
a toner concentration of 7% by weight.
[0334] Developer for Developing Electrostatic Latent Image (19)
[0335] (Aggregation Step)
47 Preparation of Aggregated Particles Resin particle dispersion
(8) 2,400 parts (contact angle with water: 86.degree.) Resin
particle dispersion (13) 600 parts (contact angle with water:
79.degree.) Colorant particle dispersion (1) 100 parts Releasing
agent particle dispersion 63 parts Lauroyl peroxide 10 parts
Aluminum sulfate 5 parts (produced by Wako Pure Chemical
Industries, Ltd.) Ion exchanged water 100 parts
[0336] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2.0. The contents of the flask
are dispersed by using a homogenizer (Ultra-Turrax T50, produced by
IKA Corp.) and heated over an oil bath for heating to 84.degree. C.
under stirring. After maintaining at 84.degree. C. for 4 hours, the
observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 6.6 .mu.m
are formed. After further maintaining at 84.degree. C. for 2 hours,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 6.9 .mu.m
are formed.
[0337] (Coalescing Step)
[0338] The aggregated particle dispersion has pH of 2.3. An aqueous
solution obtained by diluting sodium carbonate (produced by Wako
Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 4.8, and the mixture is then
heated to 98.degree. C. under continuous stirring, followed by
maintaining for 5 hours. Thereafter, the reaction product is
filtered and sufficiently washed with ion exchanged water, followed
by drying by using a vacuum dryer, so as to obtain toner
particles.
[0339] The resulting toner particles have an average particle
diameter of 7.2 .mu.m. A developer for developing an electrostatic
latent image (19) is produced by using the resulting toner
particles in the same manner as in the developer for developing an
electrostatic latent image (18).
[0340] Developer for Developing Electrostatic Latent Image (20)
[0341] (Aggregation Step)
48 Preparation of Aggregated Particles Resin particle dispersion
(9) 2,833 parts (contact angle with water: 89.degree.) Resin
particle dispersion (13) 600 parts (contact angle with water:
79.degree.) Colorant particle dispersion (1) 100 parts Releasing
agent particle dispersion 125 parts Lauroyl peroxide 12 parts
Aluminum sulfate 5 parts (produced by Wako Pure Chemical
Industries, Ltd.) Ion exchanged water 100 parts
[0342] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2.0. The contents of the flask
are dispersed by using a homogenizer (Ultra-Turrax T50, produced by
IKA Corp.) and heated over an oil bath for heating to 49.degree. C.
under stirring. After maintaining at 49.degree. C. for 2 hours, the
observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 4.0 .mu.m
are formed. After further maintaining at 49.degree. C. for 2 hours,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 4.2 .mu.m
are formed.
[0343] (Coalescing Step)
[0344] The aggregated particle dispersion has pH of 2.5. An aqueous
solution obtained by diluting sodium hydrogencarbonate (produced by
Wako Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 5.5, and the mixture is then
heated to 75.degree. C. under continuous stirring, followed by
maintaining for 4 hours. Thereafter, the reaction product is
filtered and sufficiently washed with ion exchanged water, followed
by drying by using a vacuum dryer, so as to obtain toner
particles.
[0345] The resulting toner particles have an average particle
diameter of 4.3 .mu.m. A developer for developing an electrostatic
latent image (20) is produced by using the resulting toner
particles in the same manner as in the developer for developing an
electrostatic latent image (18).
[0346] Developer for Developing Electrostatic Latent Image (21)
[0347] (Aggregation Step)
49 Preparation of Aggregated Particles Resin particle dispersion
(10) 2,400 parts (contact angle with water: 86.degree.) Resin
particle dispersion (13) 600 parts (contact angle with water:
79.degree.) Colorant particle dispersion (1) 100 parts Releasing
agent particle dispersion 63 parts Lauroyl peroxide 10 parts
Aluminum sulfate 5 parts (produced by Wako Pure Chemical
Industries, Ltd.) Ion exchanged water 100 parts
[0348] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2.0. The contents of the flask
are dispersed by using a homogenizer (Ultra-Turrax T50, produced by
IKA Corp.) and heated over an oil bath for heating to 85.degree. C.
under stirring. After maintaining at 85.degree. C. for 3 hours, the
observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 5.3 .mu.m
are formed. After further maintaining at 85.degree. C. for 2 hours,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 5.5 .mu.m
are formed.
[0349] (Coalescing Step)
[0350] The aggregated particle dispersion has pH of 2.3. An aqueous
solution obtained by diluting sodium carbonate (produced by Wako
Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 7.2, and the mixture is then
heated to 95.degree. C. under continuous stirring, followed by
maintaining for 5 hours. Thereafter, the reaction product is
filtered and sufficiently washed with ion exchanged water, followed
by drying by using a vacuum dryer, so as to obtain toner
particles.
[0351] The resulting toner particles have an average particle
diameter of 5.7 .mu.m. A developer for developing an electrostatic
latent image (21) is produced by using the resulting toner
particles in the same manner as in the developer for developing an
electrostatic latent image (18).
[0352] Developer for Developing Electrostatic Latent Image (22)
[0353] (Aggregation Step)
50 Preparation of Aggregated Particles Resin particle dispersion
(11) 2,400 parts (contact angle with water: 89.degree.) Resin
particle dispersion (13) 600 parts (contact angle with water:
79.degree.) Colorant particle dispersion (1) 100 parts Releasing
agent particle dispersion 63 parts Lauroyl peroxide 10 parts
Aluminum sulfate 5 parts (produced by Wako Pure Chemical
Industries, Ltd.) Ion exchanged water 100 parts
[0354] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2.0. The contents of the flask
are dispersed by using a homogenizer (Ultra-Turrax T50, produced by
IKA Corp.) and heated over an oil bath for heating to 64.degree. C.
under stirring. After maintaining at 64.degree. C. for 3 hours, the
observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 5.0 .mu.m
are formed. After further maintaining at 65.degree. C. for 3 hours,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 5.3 .mu.m
are formed.
[0355] (Coalescing Step)
[0356] The aggregated particle dispersion has pH of 2.4. An aqueous
solution obtained by diluting sodium carbonate (produced by Wako
Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 6.0, and the mixture is then
heated to 90.degree. C. under continuous stirring, followed by
maintaining for 5 hours. Thereafter, the reaction product is
filtered and sufficiently washed with ion exchanged water, followed
by drying by using a vacuum dryer, so as to obtain toner
particles.
[0357] The resulting toner particles have an average particle
diameter of 5.4 .mu.m. A developer for developing an electrostatic
latent image (22) is produced by using the resulting toner
particles in the same manner as in the developer for developing an
electrostatic latent image (18).
[0358] Developer for Developing Electrostatic Latent Image (23)
[0359] (Aggregation Step)
51 Preparation of Aggregated Particles Resin particle dispersion
(12) 900 parts (contact angle with water: 82.degree.) Resin
particle dispersion (14) 225 parts (contact angle with water:
78.degree.) Colorant particle dispersion (1) 100 parts Releasing
agent particle dispersion 63 parts Aluminum sulfate 5 parts
(produced by Wako Pure Chemical Industries, Ltd.) Ion exchanged
water 1,000 parts
[0360] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2.0. The contents of the flask
are dispersed by using a homogenizer (Ultra-Turrax T50, produced by
IKA Corp.) and heated over an oil bath for heating to 64.degree. C.
under stirring. After maintaining at 61.degree. C. for 3 hours, the
observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 5.0 .mu.m
are formed. After further maintaining at 61.degree. C. for 4 hours,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 5.4 .mu.m
are formed.
[0361] (Coalescing Step)
[0362] The aggregated particle dispersion has pH of 2.5. An aqueous
solution obtained by diluting sodium hydrogencarbonate (produced by
Wako Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 7.2, and the mixture is then
heated to 90.degree. C. under continuous stirring, followed by
maintaining for 6 hours. Thereafter, the reaction product is
filtered and sufficiently washed with ion exchanged water, followed
by drying by using a vacuum dryer, so as to obtain toner
particles.
[0363] The resulting toner particles have an average particle
diameter of 5.5 .mu.m. A developer for developing an electrostatic
latent image (23) is produced by using the resulting toner
particles in the same manner as in the developer for developing an
electrostatic latent image (18).
[0364] Developer for Developing Electrostatic Latent Image (24)
[0365] (Aggregation Step)
52 Preparation of Aggregated Particles Resin particle dispersion
(7) 2,850 parts (contact angle with water: 88.degree.) Resin
particle dispersion (13) 150 parts (contact angle with water:
79.degree.) Colorant particle dispersion (1) 100 parts Releasing
agent particle dispersion 63 parts Lauroyl peroxide 12 parts
Aluminum sulfate 7 parts (produced by Wako Pure Chemical
Industries, Ltd.) Ion exchanged water 150 parts
[0366] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2.0. The contents of the flask
are dispersed by using a homogenizer (Ultra-Turrax T50, produced by
IKA Corp.) and heated over an oil bath for heating to 63.degree. C.
under stirring. After maintaining at 63.degree. C. for 2 hours, the
observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 4.6 .mu.m
are formed. After further maintaining at 63.degree. C. for 3 hours,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 4.8 .mu.m
are formed.
[0367] (Coalescing Step)
[0368] The aggregated particle dispersion has pH of 2.7. An aqueous
solution obtained by diluting sodium hydrogencarbonate (produced by
Wako Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 5.3, and the mixture is then
heated to 90.degree. C. under continuous stirring, followed by
maintaining for 6 hours. Thereafter, the reaction product is
filtered and sufficiently washed with ion exchanged water, followed
by drying by using a vacuum dryer, so as to obtain toner
particles.
[0369] The resulting toner particles have an average particle
diameter of 4.8 .mu.m. A developer for developing an electrostatic
latent image (24) is produced by using the resulting toner
particles in the same manner as in the developer for developing an
electrostatic latent image (18).
[0370] Developer for Developing Electrostatic Latent Image (25)
[0371] (Aggregation Step)
53 Preparation of Aggregated Particles Resin particle dispersion
(7) 1,650 parts (contact angle with water: 88.degree.) Resin
particle dispersion (13) 1,350 parts (contact angle with water:
79.degree.) Colorant particle dispersion (1) 100 parts Releasing
agent particle dispersion 63 parts Lauroyl peroxide 7 parts
Aluminum sulfate 7 parts (produced by Wako Pure Chemical
Industries, Ltd.) Ion exchanged water 120 parts
[0372] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2.0. The contents of the flask
are dispersed by using a homogenizer (Ultra-Turrax T50, produced by
IKA Corp.) and heated over an oil bath for heating to 65.degree. C.
under stirring. After maintaining at 65.degree. C. for 3 hours, the
observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 4.1 .mu.m
are formed. After further maintaining at 65.degree. C. for 2 hours,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 4.3 .mu.m
are formed.
[0373] (Coalescing Step)
[0374] The aggregated particle dispersion has pH of 2.3. An aqueous
solution obtained by diluting sodium hydrogencarbonate (produced by
Wako Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 5.2, and the mixture is then
heated to 90.degree. C. under continuous stirring, followed by
maintaining for 4 hours. Thereafter, the reaction product is
filtered and sufficiently washed with ion exchanged water, followed
by drying by using a vacuum dryer, so as to obtain toner
particles.
[0375] The resulting toner particles have an average particle
diameter of 4.4 .mu.m. A developer for developing an electrostatic
latent image (25) is produced by using the resulting toner
particles in the same manner as in the developer for developing an
electrostatic latent image (18).
[0376] Developer for Developing Electrostatic Latent Image (26)
[0377] (Aggregation Step)
54 Preparation of Aggregated Particles Resin particle dispersion
(7) 2,347 parts (contact angle with water: 88.degree.) Resin
particle dispersion (13) 587 parts (contact angle with water:
79.degree.) Colorant particle dispersion (3) 117 parts Releasing
agent particle dispersion 63 parts Lauroyl peroxide 10 parts
Aluminum sulfate 5 parts (produced by Wako Pure Chemical
Industries, Ltd.) Ion exchanged water 100 parts
[0378] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2.1. The contents of the flask
are dispersed by using a homogenizer (Ultra-Turrax T50, produced by
IKA Corp.) and heated over an oil bath for heating to 68.degree. C.
under stirring. After maintaining at 68.degree. C. for 3 hours, the
observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 4.8 .mu.m
are formed. After further maintaining at 68.degree. C. for 2 hours,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 5.0 .mu.m
are formed.
[0379] (Coalescing Step)
[0380] The aggregated particle dispersion has pH of 2.6. An aqueous
solution obtained by diluting sodium carbonate (produced by Wako
Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 5.9, and the mixture is then
heated to 85.degree. C. under continuous stirring, followed by
maintaining for 3 hours. Thereafter, the reaction product is
filtered and sufficiently washed with ion exchanged water, followed
by drying by using a vacuum dryer, so as to obtain toner
particles.
[0381] The resulting toner particles have an average particle
diameter of 5.2 .mu.m. A developer for developing an electrostatic
latent image (26) is produced by using the resulting toner
particles in the same manner as in the developer for developing an
electrostatic latent image (18).
[0382] Developer for Developing Electrostatic Latent Image (27)
[0383] (Aggregation Step)
55 Preparation of Aggregated Particles Resin particle dispersion
(7) 2,267 parts (contact angle with water: 88.degree.) Resin
particle dispersion (13) 567 parts (contact angle with water:
79.degree.) Colorant particle dispersion (2) 250 parts Releasing
agent particle dispersion 63 parts Aluminum sulfate 5 parts
(produced by Wako Pure Chemical Industries, Ltd.) Ion exchanged
water 100 parts
[0384] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2.1. The contents of the flask
are dispersed by using a homogenizer (Ultra-Turrax T50, produced by
IKA Corp.) and heated over an oil bath for heating to 68.degree. C.
under stirring. After maintaining at 68.degree. C. for 3 hours, the
observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 4.9 .mu.m
are formed. After further maintaining at 68.degree. C. for 3 hours,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 5.3 .mu.m
are formed.
[0385] (Coalescing Step)
[0386] The aggregated particle dispersion has pH of 2.3. An aqueous
solution obtained by diluting sodium carbonate (produced by Wako
Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 5.5, and the mixture is then
heated to 85.degree. C. under continuous stirring, followed by
maintaining for 3 hours. Thereafter, the reaction product is
filtered and sufficiently washed with ion exchanged water, followed
by drying by using a vacuum dryer, so as to obtain toner
particles.
[0387] The resulting toner particles have an average particle
diameter of 5.2 .mu.m. A developer for developing an electrostatic
latent image (27) is produced by using the resulting toner
particles in the same manner as in the developer for developing an
electrostatic latent image (18).
[0388] Developer for Developing Electrostatic Latent Image (28)
[0389] (Aggregation Step)
56 Preparation of Aggregated Particles Resin particle dispersion
(7) 2,400 parts (contact angle with water: 88.degree.) Resin
particle dispersion (13) 600 parts (contact angle with water:
79.degree.) Colorant particle dispersion (4) 109 parts Releasing
agent particle dispersion 63 parts Lauroyl peroxide 10 parts
Aluminum sulfate 5 parts (produced by Wako Pure Chemical
Industries, Ltd.) Ion exchanged water 100 parts
[0390] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2.0. The contents of the flask
are dispersed by using a homogenizer (Ultra-Turrax T50, produced by
IKA Corp.) and heated over an oil bath for heating to 65.degree. C.
under stirring. After maintaining at 68.degree. C. for 2 hours, the
observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 4.9 .mu.m
are formed. After further maintaining at 65.degree. C. for 3 hours,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 5.3 .mu.m
are formed.
[0391] (Coalescing Step)
[0392] The aggregated particle dispersion has pH of 2.3. An aqueous
solution obtained by diluting sodium carbonate (produced by Wako
Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 5.6, and the mixture is then
heated to 90.degree. C. under continuous stirring, followed by
maintaining for 4 hours. Thereafter, the reaction product is
filtered and sufficiently washed with ion exchanged water, followed
by drying by using a vacuum dryer, so as to obtain toner
particles.
[0393] The resulting toner particles have an average particle
diameter of 5.5 .mu.m. A developer for developing an electrostatic
latent image (28) is produced by using the resulting toner
particles in the same manner as in the developer for developing an
electrostatic latent image (18).
[0394] Developer for Developing Electrostatic Latent Image (29)
[0395] (Aggregation Step)
57 Preparation of Aggregated Particles Resin particle dispersion
(7) 2,400 parts (contact angle with water: 88.degree.) Resin
particle dispersion (14) 225 parts (contact angle with water:
78.degree.) Colorant particle dispersion (1) 109 parts Releasing
agent particle dispersion 65 parts Lauroyl peroxide 10 parts
Aluminum sulfate 5 parts (produced by Wako Pure Chemical
Industries, Ltd.) Ion exchanged water 100 parts
[0396] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2.0. The contents of the flask
are dispersed by using a homogenizer (Ultra-Turrax T50, produced by
IKA Corp.) and heated over an oil bath for heating to 66.degree. C.
under stirring. After maintaining at 65.degree. C. for 3 hours, the
observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 4.3 .mu.m
are formed. After further maintaining at 65.degree. C. for 2 hours,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 4.5 .mu.m
are formed.
[0397] (Coalescing Step)
[0398] The aggregated particle dispersion has pH of 2.6. An aqueous
solution obtained by diluting sodium carbonate (produced by Wako
Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 5.9, and the mixture is then
heated to 90.degree. C. under continuous stirring, followed by
maintaining for 4 hours. Thereafter, the reaction product is
filtered and sufficiently washed with ion exchanged water, followed
by drying by using a vacuum dryer, so as to obtain toner
particles.
[0399] The resulting toner particles have an average particle
diameter of 4.8 .mu.m. A developer for developing an electrostatic
latent image (29) is produced by using the resulting toner
particles in the same manner as in the developer for developing an
electrostatic latent image (18).
[0400] Developer for Developing Electrostatic Latent Image (30)
[0401] (Aggregation Step)
58 Preparation of Aggregated Particles Resin particle dispersion
(12) 900 parts (contact angle with water: 82.degree.) Resin
particle dispersion (13) 600 parts (contact angle with water:
79.degree.) Colorant particle dispersion (1) 100 parts Releasing
agent particle dispersion 63 parts Lauroyl peroxide 10 parts
Aluminum sulfate 5 parts (produced by Wako Pure Chemical
Industries, Ltd.) Ion exchanged water 100 parts
[0402] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2.0. The contents of the flask
are dispersed by using a homogenizer (Ultra-Turrax T50, produced by
IKA Corp.) and heated over an oil bath for heating to 65.degree. C.
under stirring. After maintaining at 65.degree. C. for 3 hours, the
observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 5.3 .mu.m
are formed. After further maintaining at 65.degree. C. for 2 hours,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 5.6 .mu.m
are formed.
[0403] (Coalescing Step)
[0404] The aggregated particle dispersion has pH of 2.3. An aqueous
solution obtained by diluting sodium carbonate (produced by Wako
Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 5.0, and the mixture is then
heated to 90.degree. C. under continuous stirring, followed by
maintaining for 4 hours. Thereafter, the reaction product is
filtered and sufficiently washed with ion exchanged water, followed
by drying by using a vacuum dryer, so as to obtain toner
particles.
[0405] The resulting toner particles have an average particle
diameter of 5.7 .mu.m. A developer for developing an electrostatic
latent image (30) is produced by using the resulting toner
particles in the same manner as in the developer for developing an
electrostatic latent image (18).
[0406] Developer for Developing Electrostatic Latent Image (31)
[0407] (Aggregation Step)
59 Preparation of Aggregated Particles Resin particle dispersion
(7) 3,000 parts (contact angle with water: 88.degree.) Colorant
particle dispersion (1) 100 parts Releasing agent particle
dispersion 63 parts Lauroyl peroxide 10 parts Aluminum sulfate 5
parts (produced by Wako Pure Chemical Industries, Ltd.) Ion
exchanged water 100 parts
[0408] The foregoing components are placed in a round flask made of
stainless steel and adjusted to pH 2.0. The contents of the flask
are dispersed by using a homogenizer (Ultra-Turrax T50, produced by
IKA Corp.) and heated over an oil bath for heating to 65.degree. C.
under stirring. After maintaining at 65.degree. C. for 2 hours, the
observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 5.1 .mu.m
are formed. After further maintaining at 65.degree. C. for 2 hours,
the observation by an optical microscope confirms that aggregated
particles having an average particle diameter of about 5.3 .mu.m
are formed.
[0409] (Coalescing Step)
[0410] The aggregated particle dispersion has pH of 2.2. An aqueous
solution obtained by diluting sodium carbonate (produced by Wako
Pure Chemical Industries, Ltd.) to 0.5% by weight is gradually
added thereto to adjust the pH to 4.5, and the mixture is then
heated to 90.degree. C. under continuous stirring, followed by
maintaining for 4 hours. Thereafter, the reaction product is
filtered and sufficiently washed with ion exchanged water, followed
by drying by using a vacuum dryer, so as to obtain toner
particles.
[0411] The resulting toner particles have an average particle
diameter of 5.5 .mu.m. A developer for developing an electrostatic
latent image (31) is produced by using the resulting toner
particles in the same manner as in the developer for developing an
electrostatic latent image (18).
EXAMPLE 17
[0412] A modified machine of a color duplicator, Acolor 930,
produced by Fuji Xerox Co., Ltd. is prepared in the following
manner. The releasing oil supplying unit of the duplicator is
detached, and a fixing unit containing a fixing roll and a pressure
roll, which are covered with films of a ethylene-vinylidene
fluoride-tetrafluoroethylene copolymer on the surfaces thereof, is
installed. The developer for developing an electrostatic latent
image (18) is installed in a developer of the modified duplicator,
and a non-fixed image is prepared to have a solid part and a thin
line part. The non-fixed image is fixed in such a manner that the
rotation speed of the roll is adjusted to make the contact time of
the fixing roll and the non-fixed image be 0.04 second, with the
surface temperature of the fixing roll varying from 60 to
200.degree. C. at an interval of 5.degree. C. The fixed image is
folded inside at the substantial center of the solid part of the
fixed image to evaluate the breakage of the fixed image, and the
fixing temperature where no problem occurs is designated as the
lowest fixing temperature. Reproducibility of the thin lines,
background fogging and hot offset are evaluated with the naked eye.
Furthermore, the toner used is evaluated for the characteristics,
the particle size, the particle size distribution and the fixing
characteristics. The results are shown in Tables 3 and 4 below.
[0413] In the tables, Tm represents the melting point of the toner,
GL(30) represents the storage elastic modulus at 30.degree. C.;
GL(Tm) and GL(Tm+10) represent the storage elastic modulus at the
melting point and that at a temperature higher by 10.degree. C.
than the melting point, respectively; GN(Tm) and GN(Tm+10)
represent the loss elastic modulus at the melting point and that at
a temperature higher by 10.degree. C. than the melting point,
respectively; .DELTA.log GL represents .vertline.log GL(Tm+20)-log
GL(Tm+50).vertline.; and .DELTA.log GN represents .vertline.log
GN(Tm+20)-log GN(Tm+50).vertline..
EXAMPLES 18 TO 29
Comparative Examples 4
[0414] Evaluation is conducted in the same manner as in Example 17
except that the developers for developing an electrostatic latent
image (19) to (31) are used instead of the developer for developing
an electrostatic latent image (18). The results are shown in Tables
3 and 4.
60 TABLE 3 Tm GL(30) .times. GL(Tm) .times. GL(Tm + 10) .times.
GN(Tm) .times. GN(Tm + 10) .times. Developer (` C.) 10.sup.5
10.sup.5 10.sup.3 10.sup.5 10.sup.3 .DELTA.log GL .DELTA.log GN
Example 17 18 69 3.2 2.8 4.2 4.0 4.6 1.2 1.2 Example 18 19 85 5.9
6.6 6.2 7.0 5.2 1.2 1.3 Example 19 20 60 1.5 1.2 9.2 3.1 8.2 1.1
1.0 Example 20 21 81 4.8 4.0 2.2 6.5 2.5 0.2 0.4 Example 21 22 67
8.0 7.6 1.5 9.3 1.3 0.7 0.5 Example 22 23 60 3.5 3.4 8.3 3.9 8.0
0.3 0.4 Example 23 24 71 3.2 2.8 5.2 4.1 8.5 1.1 1.3 Example 24 25
66 3.2 2.8 4.8 4.0 4.5 1.0 1.0 Example 25 26 69 3.2 2.8 5.0 4.3 4.5
0.8 0.7 Example 26 27 69 3.2 2.8 4.9 4.2 5.1 1.2 1.1 Example 27 28
69 3.2 2.8 4.6 4.3 4.6 0.8 0.5 Example 28 29 69 3.2 2.8 3.8 4.2 1.6
0.9 0.5 Example 29 30 61 3.2 2.8 5.2 4.2 4.0 1.1 1.5 Comparative 31
72 3.1 2.6 3.2 4.6 1.2 1.3 1.0 Example 4
[0415]
61 TABLE 4 Average Fixing Reproduci- diameter temperature bility of
Background Developer (.mu.m) GSDv Tan .delta. (.degree. C.) thin
lines fogging Hot offset Example 17 18 5.3 1.21 0.91 85 good none
no occurrence Example 18 19 7.2 1.20 1.19 100 good none no
occurrence Example 19 20 4.3 1.24 1.12 75 good none no occurrence
Example 20 21 5.7 1.22 0.88 95 good none no occurrence Example 21
22 5.4 1.22 1.15 80 good none no occurrence Example 22 23 5.5 1.23
1.04 80 good none no occurrence Example 23 24 4.8 1.20 0.63 85 good
none no occurrence Example 24 25 4.4 1.22 1.07 90 good none no
occurrence Example 25 26 5.2 1.20 1.11 85 good none no occurrence
Example 26 27 5.2 1.25 0.96 85 good none no occurrence Example 27
28 5.5 1.25 1.00 85 good none no occurrence Example 28 29 4.8 1.25
2.38 85 good none no occurrence Example 29 30 5.7 1.24 1.30 85 good
none no occurrence Comparative 31 5.5 1.38 2.67 85 slightly poor
slight no Example 4 occurrence occurrence
[0416] It is understood from Tables 3 and 4 that when the
developers for developing an electrostatic latent image containing
the toners for developing an electrostatic latent image in Examples
17 to 29 are used, in comparison to the developer for developing an
electrostatic latent image containing the toner for developing an
electrostatic latent image in Comparative Example 4, the particle
size distribution becomes narrow, i.e., the particle diameters of
the respective particles of the toner can be uniformized, and
therefore the toners are excellent in reproducibility of thin
lines, cause no background fogging, and are excellent in low
temperature fixing property. Furthermore, it is also understood
that the toners are excellent in image stability upon high speed
fixing particularly in the case where a color toner is used.
[0417] Owing to the foregoing constitution, the invention can
provide a toner for developing an electrostatic latent image having
excellent low temperature fixing property and containing a colorant
and a releasing agent uniformly dispersed. The invention can
provide a toner for developing an electrostatic latent image and a
process for producing the same, as well as a developer for
developing an electrostatic latent image and a process for forming
an image using the same, which toner is produced by a simple
production process, has good reproducibility particularly in
particle size and particle size distribution, is excellent in
production stability, has a wide fixing region, and is excellent in
low temperature fixing property. The invention can provide a toner
for developing an electrostatic latent image and a process for
producing the same, as well as a developer for developing an
electrostatic latent image and a process for forming an image using
the same, which toner is excellent in production stability and
storage stability of resin particles formed by the aggregation
process, and is excellent in charging property, particularly
environmental stability and time-lapse stability, whereby an
excellent image can be formed even by a machine using a belt type
fixing unit or a high speed fixing unit, which have a low heating
ability upon fixing.
[0418] The entire disclosure of Japanese Patent Applications No.
2000-260311 filed on Aug. 30, 2000 including specification, claims,
drawings and abstract and No. 2000-303912 filed on Oct. 3, 2000
including specification, claims and abstract is incorporated herein
by reference in its entirety.
* * * * *